diff --git a/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.sgml b/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.sgml index 640d4f2fc8..1d1b221468 100644 --- a/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.sgml +++ b/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.sgml @@ -1,3787 +1,3877 @@ Advanced Networking Synopsis The following chapter will cover some of the more frequently used network services on UNIX systems. This, of course, will pertain to configuring said services on your FreeBSD system. Gateways and Routes Contributed by &a.gryphon;. 6 October 1995. route routing gateway subnet For one machine to be able to find another, there must be a mechanism in place to describe how to get from one to the other. This is called Routing. A route is a defined pair of addresses: a destination and a gateway. The pair indicates that if you are trying to get to this destination, send along through this gateway. There are three types of destinations: individual hosts, subnets, and default. The default route is used if none of the other routes apply. We will talk a little bit more about default routes later on. There are also three types of gateways: individual hosts, interfaces (also called links), and ethernet hardware addresses. An example To illustrate different aspects of routing, we will use the following example which is the output of the command netstat -r: Destination Gateway Flags Refs Use Netif Expire default outside-gw UGSc 37 418 ppp0 localhost localhost UH 0 181 lo0 test0 0:e0:b5:36:cf:4f UHLW 5 63288 ed0 77 10.20.30.255 link#1 UHLW 1 2421 foobar.com link#1 UC 0 0 host1 0:e0:a8:37:8:1e UHLW 3 4601 lo0 host2 0:e0:a8:37:8:1e UHLW 0 5 lo0 => host2.foobar.com link#1 UC 0 0 224 link#1 UC 0 0 default route The first two lines specify the default route (which we will cover in the next section) and the localhost route. loopback device The interface (Netif column) that it specifies to use for localhost is lo0, also known as the loopback device. This says to keep all traffic for this destination internal, rather than sending it out over the LAN, since it will only end up back where it started anyway. - EthernetMAC address + + Ethernet + MAC address + The next thing that stands out are the 0:e0:... addresses. These are ethernet hardware addresses. FreeBSD will automatically identify any hosts (test0 in the example) on the local ethernet and add a route for that host, directly to it over the ethernet interface, ed0. There is also a timeout (Expire column) associated with this type of route, which is used if we fail to hear from the host in a specific amount of time. In this case the route will be automatically deleted. These hosts are identified using a mechanism known as RIP (Routing Information Protocol), which figures out routes to local hosts based upon a shortest path determination. subnet FreeBSD will also add subnet routes for the local subnet (10.20.30.255 is the broadcast address for the subnet 10.20.30, and foobar.com is the domain name associated with that subnet). The designation link#1 refers to the first ethernet card in the machine. You will notice no additional interface is specified for those. Both of these groups (local network hosts and local subnets) have their routes automatically configured by a daemon called routed. If this is not run, then only routes which are statically defined (ie. entered explicitly) will exist. The host1 line refers to our host, which it knows by ethernet address. Since we are the sending host, FreeBSD knows to use the loopback interface (lo0) rather than sending it out over the ethernet interface. The two host2 lines are an example of what happens when we use an ifconfig alias (see the section of ethernet for reasons why we would do this). The => symbol after the lo0 interface says that not only are we using the loopback (since this is address also refers to the local host), but specifically it is an alias. Such routes only show up on the host that supports the alias; all other hosts on the local network will simply have a link#1 line for such. The final line (destination subnet 224) deals with MultiCasting, which will be covered in a another section. The other column that we should talk about are the Flags. Each route has different attributes that are described in the column. Below is a short table of some of these flags and their meanings: U Up: The route is active. H Host: The route destination is a single host. G Gateway: Send anything for this destination on to this remote system, which will figure out from there where to send it. S Static: This route was configured manually, not automatically generated by the system. C Clone: Generates a new route based upon this route for machines we connect to. This type of route is normally used for local networks. W WasCloned: Indicated a route that was auto-configured based upon a local area network (Clone) route. L Link: Route involves references to ethernet hardware. Default routes default route When the local system needs to make a connection to remote host, it checks the routing table to determine if a known path exists. If the remote host falls into a subnet that we know how to reach (Cloned routes), then the system checks to see if it can connect along that interface. If all known paths fail, the system has one last option: the default route. This route is a special type of gateway route (usually the only one present in the system), and is always marked with a c in the flags field. For hosts on a local area network, this gateway is set to whatever machine has a direct connection to the outside world (whether via PPP link, or your hardware device attached to a dedicated data line). If you are configuring the default route for a machine which itself is functioning as the gateway to the outside world, then the default route will be the gateway machine at your Internet Service Provider's (ISP) site. Let us look at an example of default routes. This is a common configuration: [Local2] <--ether--> [Local1] <--PPP--> [ISP-Serv] <--ether--> [T1-GW] The hosts Local1 and Local2 are at your site, with the formed being your PPP connection to your ISP's Terminal Server. Your ISP has a local network at their site, which has, among other things, the server where you connect and a hardware device (T1-GW) attached to the ISP's Internet feed. The default routes for each of your machines will be: host default gateway interface Local2 Local1 ethernet Local1 T1-GW PPP A common question is Why (or how) would we set the T1-GW to be the default gateway for Local1, rather than the ISP server it is connected to?. Remember, since the PPP interface is using an address on the ISP's local network for your side of the connection, routes for any other machines on the ISP's local network will be automatically generated. Hence, you will already know how to reach the T1-GW machine, so there is no need for the intermediate step of sending traffic to the ISP server. As a final note, it is common to use the address ...1 as the gateway address for your local network. So (using the same example), if your local class-C address space was 10.20.30 and your ISP was using 10.9.9 then the default routes would be: Local2 (10.20.30.2) --> Local1 (10.20.30.1) Local1 (10.20.30.1, 10.9.9.30) --> T1-GW (10.9.9.1) Dual homed hosts dual homed hosts There is one other type of configuration that we should cover, and that is a host that sits on two different networks. Technically, any machine functioning as a gateway (in the example above, using a PPP connection) counts as a dual-homed host. But the term is really only used to refer to a machine that sits on two local-area networks. In one case, the machine as two ethernet cards, each having an address on the separate subnets. Alternately, the machine may only have one ethernet card, and be using ifconfig aliasing. The former is used if two physically separate ethernet networks are in use, the latter if there is one physical network segment, but two logically separate subnets. Either way, routing tables are set up so that each subnet knows that this machine is the defined gateway (inbound route) to the other subnet. This configuration, with the machine acting as a Bridge between the two subnets, is often used when we need to implement packet filtering or firewall security in either or both directions. Routing propagation routing propogation We have already talked about how we define our routes to the outside world, but not about how the outside world finds us. We already know that routing tables can be set up so that all traffic for a particular address space (in our examples, a class-C subnet) can be sent to a particular host on that network, which will forward the packets inbound. When you get an address space assigned to your site, your service provider will set up their routing tables so that all traffic for your subnet will be sent down your PPP link to your site. But how do sites across the country know to send to your ISP? There is a system (much like the distributed DNS information) that keeps track of all assigned address-spaces, and defines their point of connection to the Internet Backbone. The Backbone are the main trunk lines that carry Internet traffic across the country, and around the world. Each backbone machine has a copy of a master set of tables, which direct traffic for a particular network to a specific backbone carrier, and from there down the chain of service providers until it reaches your network. It is the task of your service provider to advertise to the backbone sites that they are the point of connection (and thus the path inward) for your site. This is known as route propagation. Troubleshooting traceroute Sometimes, there is a problem with routing propagation, and some sites are unable to connect to you. Perhaps the most useful command for trying to figure out where a routing is breaking down is the &man.traceroute.8; command. It is equally useful if you cannot seem to make a connection to a remote machine (i.e. &man.ping.8; fails). The &man.traceroute.8; command is run with the name of the remote host you are trying to connect to. It will show the gateway hosts along the path of the attempt, eventually either reaching the target host, or terminating because of a lack of connection. For more information, see the manual page for &man.traceroute.8;. Bridging Written by Steve Peterson steve@zpfe.com. Introduction IP subnet bridge It is sometimes useful to divide one physical network (i.e., an Ethernet segment) into two separate network segments, without having to create IP subnets and use a router to connect the segments together. A device that connects two networks together in this fashion is called a bridge. and a FreeBSD system with two network interface cards can act as a bridge. The bridge works by learning the MAC layer addresses (i.e., Ethernet addresses) of the devices on each of its network interfaces. It forwards traffic between two networks only when its source and destination are on different networks. In many respects, a bridge is like an Ethernet switch with very few ports. Situations where bridging is appropriate There are two common situations in which a bridge is used today. High traffic on a segment Situation one is where your physical network segment is overloaded with traffic, but you don't want for whatever reason to subnet the network and interconnect the subnets with a router. Let's consider an example of a newspaper where the Editorial and Production departments are on the same subnetwork. The Editorial users all use server A for file service, and the Production users are on server B. An Ethernet is used to connect all users together, and high loads on the network are slowing things down. If the Editorial users could be segregated on one network segment and the Production users on another, the two network segments could be connected with a bridge. Only the network traffic destined for interfaces on the "other" side of the bridge would be sent to the other network, reducing congestion on each network segment. Filtering/traffic shaping firewall firewall IP Masquerading The second common situation is where firewall functionality is needed without IP Masquerading (NAT). An example is a small company that is connected via DSL or ISDN to their ISP. They have a 13 address global IP allocation for their ISP and have 10 PCs on their network. In this situation, using a router-based firewall is difficult because of subnetting issues. router DSL ISDN A bridge-based firewall can be configured and dropped into the path just downstream of their DSL/ISDN router without any IP numbering issues. Configuring a bridge Network interface card selection A bridge requires at least two network cards to function. Unfortunately, not all network interface cards as of FreeBSD 4.0 support bridging. Read &man.bridge.4; for details on the cards that are supported. Install and test the two network cards before continuing. Kernel configuration changes kernel configuration - kernel configurationoptions BRIDGE + + kernel configuration + options BRIDGE + To enable kernel support for bridging, add the options BRIDGE statement to your kernel configuration file, and rebuild your kernel. Firewall support firewall If you are planning to use the bridge as a firewall, you will need to add the IPFIREWALL option as well. Read for general information on configuring the bridge as a firewall. If you need to allow non-IP packets (such as ARP) to flow through the bridge, there is an undocumented firewall option that must be set. This option is IPFIREWALL_DEFAULT_TO_ACCEPT. Note that this changes the default rule for the firewall to accept any packet. Make sure you know how this changes the meaning of your ruleset before you set it. Traffic shaping support If you want to use the bridge as a traffic shaper, you will need to add the DUMMYNET option to your kernel configuration. Read &man.dummynet.4; for further information. Enabling the bridge Add the line net.link.ether.bridge=1 to /etc/sysctl.conf to enable the bridge at runtime. If you want the bridged packets to be filtered by ipfw, you should also add net.link.ether.bridge_ipfw=1 as well. Performance My bridge/firewall is a Pentium 90 with one 3Com 3C900B and one 3C905B. The protected side of the network runs at 10mbps half duplex and the connection between the bridge and my router (a Cisco 675) runs at 100mbps full duplex. With no filtering enabled, I've found that the bridge adds about 0.4 milliseconds of latency to pings from the protected 10mbps network to the Cisco 675. Other information If you want to be able to telnet into the bridge from the network, it is OK to assign one of the network cards an IP address. The consensus is that assigning both cards an address is a bad idea. If you have multiple bridges on your network, there cannot be more than one path between any two workstations. Technically, this means that there is no support for spanning tree link management. NFS Written by &a.unfurl;, 4 March 2000. NFS Among the many different file systems that FreeBSD supports is a very unique type, the Network File System or NFS. NFS allows you to share directories and files on one machine with one or more other machines via the network they are attached to. Using NFS, users and programs can access files on remote systems as if they were local files. NFS has several benefits: Local workstations don't need as much disk space because commonly used data can be stored on a single machine and still remain accessible to everyone on the network. There is no need for users to have unique home directories on every machine on your network. Once they have an established directory that is available via NFS it can be accessed from anywhere. Storage devices such as floppies and CD-ROM drives can be used by other machines on the network eliminating the need for extra hardware. How It Works NFS is composed of two sides – a client side and a server side. Think of it as a want/have relationship. The client wants the data that the server side has. The server shares its data with the client. In order for this system to function properly a few processes have to be configured and running properly. The server has to be running the following daemons: - NFSserver + + NFS + server + portmap mountd nfsd nfsd - The NFS Daemon which services requests from NFS clients. mountd - The NFS Mount Daemon which actually carries out requests that nfsd passes on to it. portmap - The portmapper daemon which allows NFS clients to find out which port the NFS server is using. The client side only needs to run a single daemon: - NFSclient + + NFS + client + nfsiod nfsiod - The NFS async I/O Daemon which services requests from its NFS server. Configuring NFS - NFSconfiguration + + NFS + configuration + Luckily for us, on a FreeBSD system this setup is a snap. The processes that need to be running can all be run at boot time with a few modifications to your /etc/rc.conf file. On the NFS server make sure you have: portmap_enable="YES" nfs_server_enable="YES" nfs_server_flags="-u -t -n 4" mountd_flags="-r" mountd is automatically run whenever the NFS server is enabled. The and flags to nfsd tell it to serve UDP and TCP clients. The flag tells nfsd to start 4 copies of itself. On the client, make sure you have: nfs_client_enable="YES" nfs_client_flags="-n 4" Like nfsd, the tells nfsiod to start 4 copies of itself. The last configuration step requires that you create a file called /etc/exports. The exports file specifies which file systems on your server will be shared (a.k.a., exported) and with what clients they will be shared. Each line in the file specifies a file system to be shared. There are a handful of options that can be used in this file but only a few will be mentioned here. You can find out about the rest in the &man.exports.5; man page. Here are a few example /etc/exports entries: - NFSexporting filesystems + + NFS + exporting filesystems + The following line exports /cdrom to three silly machines that have the same domain name as the server (hence the lack of a domain name for each) or have entries in your /etc/hosts file. The flag makes the shared file system read-only. With this flag, the remote system will not be able to make any changes to the shared file system. /cdrom -ro moe larry curly The following line exports /home to three hosts by IP address. This is a useful setup if you have a private network but do not have DNS running. The flag allows all the directories below the specified file system to be exported as well. /home -alldirs 10.0.0.2 10.0.0.3 10.0.0.4 The following line exports /a to two machines that have different domain names than the server. The flag allows the root user on the remote system to write to the shared file system as root. Without the -maproot=0 flag even if someone has root access on the remote system they won't be able to modify files on the shared file system. /a -maproot=0 host.domain.com box.example.com In order for a client to share an exported file system it must have permission to do so. Make sure your client is listed in your /etc/exports file. It's important to remember that you must restart mountd whenever you modify /etc/exports so that your changes take effect. This can be accomplished by sending the hangup signal to the mountd process : &prompt.root; kill -HUP `cat /var/run/mountd.pid` Now that you have made all these changes you can just reboot and let FreeBSD start everything for you at boot time or you can run the following commands as root: On the NFS server: &prompt.root; portmap &prompt.root; nfsd -u -t -n 4 &prompt.root; mountd -r On the NFS client: &prompt.root; nfsiod -n 4 Now you should be ready to actually mount a remote file system. This can be done one of two ways. In these examples the server's name will be server and the client's name will be client. If you just want to temporarily mount a remote file system or just want to test out your config you can run a command like this as root on the client: - NFSmounting filesystems + + NFS + mounting filesystems + &prompt.root; mount server:/home /mnt This will mount /home on the server on /mnt on the client. If everything is setup correctly you should be able to go into /mnt on the client and see all the files that are on the server. If you want to permanently (each time you reboot) mount a remote file system you need to add it to your /etc/fstab file. Here is an example line: server:/home /mnt nfs rw 0 0 Read the &man.fstab.5; man page for more options. Practical Uses There are many very cool uses for NFS. Some of the more common ones are listed below. - NFSuses + + NFS + uses + Have several machines on a network and share a CD-ROM or floppy drive among them. This is cheaper and often more convenient. With so many machines on a network, it gets old having your personal files strewn all over the place. You can have a central NFS server that houses all user home directories and shares them with the rest of the machines on the LAN, so no matter where you log in you will have the same home directory. When you get to reinstalling FreeBSD on one of your machines, NFS is the way to go! Just pop your distribution CD-ROM into your file server and away you go! Have a common /usr/ports/distfiles directory that all your machines share. That way, when you go to install a port that you've already installed on a different machine, you do not have to download the source all over again! Problems integrating with other systems Contributed by &a.jlind;. Certain Ethernet adapters for ISA PC systems have limitations which can lead to serious network problems, particularly with NFS. This difficulty is not specific to FreeBSD, but FreeBSD systems are affected by it. The problem nearly always occurs when (FreeBSD) PC systems are networked with high-performance workstations, such as those made by Silicon Graphics, Inc., and Sun Microsystems, Inc. The NFS mount will work fine, and some operations may succeed, but suddenly the server will seem to become unresponsive to the client, even though requests to and from other systems continue to be processed. This happens to the client system, whether the client is the FreeBSD system or the workstation. On many systems, there is no way to shut down the client gracefully once this problem has manifested itself. The only solution is often to reset the client, because the NFS situation cannot be resolved. Though the correct solution is to get a higher performance and capacity Ethernet adapter for the FreeBSD system, there is a simple workaround that will allow satisfactory operation. If the FreeBSD system is the server, include the option on the mount from the client. If the FreeBSD system is the client, then mount the NFS file system with the option . These options may be specified using the fourth field of the fstab entry on the client for automatic mounts, or by using the parameter of the mount command for manual mounts. It should be noted that there is a different problem, sometimes mistaken for this one, when the NFS servers and clients are on different networks. If that is the case, make certain that your routers are routing the necessary UDP information, or you will not get anywhere, no matter what else you are doing. In the following examples, fastws is the host (interface) name of a high-performance workstation, and freebox is the host (interface) name of a FreeBSD system with a lower-performance Ethernet adapter. Also, /sharedfs will be the exported NFS filesystem (see man exports), and /project will be the mount point on the client for the exported file system. In all cases, note that additional options, such as or and may be desirable in your application. Examples for the FreeBSD system (freebox) as the client: in /etc/fstab on freebox: fastws:/sharedfs /project nfs rw,-r=1024 0 0 As a manual mount command on freebox: &prompt.root; mount -t nfs -o -r=1024 fastws:/sharedfs /project Examples for the FreeBSD system as the server: in /etc/fstab on fastws: freebox:/sharedfs /project nfs rw,-w=1024 0 0 As a manual mount command on fastws: &prompt.root; mount -t nfs -o -w=1024 freebox:/sharedfs /project Nearly any 16-bit Ethernet adapter will allow operation without the above restrictions on the read or write size. For anyone who cares, here is what happens when the failure occurs, which also explains why it is unrecoverable. NFS typically works with a block size of 8k (though it may do fragments of smaller sizes). Since the maximum Ethernet packet is around 1500 bytes, the NFS block gets split into multiple Ethernet packets, even though it is still a single unit to the upper-level code, and must be received, assembled, and acknowledged as a unit. The high-performance workstations can pump out the packets which comprise the NFS unit one right after the other, just as close together as the standard allows. On the smaller, lower capacity cards, the later packets overrun the earlier packets of the same unit before they can be transferred to the host and the unit as a whole cannot be reconstructed or acknowledged. As a result, the workstation will time out and try again, but it will try again with the entire 8K unit, and the process will be repeated, ad infinitum. By keeping the unit size below the Ethernet packet size limitation, we ensure that any complete Ethernet packet received can be acknowledged individually, avoiding the deadlock situation. Overruns may still occur when a high-performance workstations is slamming data out to a PC system, but with the better cards, such overruns are not guaranteed on NFS units. When an overrun occurs, the units affected will be retransmitted, and there will be a fair chance that they will be received, assembled, and acknowledged. Diskless Operation Contributed by &a.martin;. diskless workstation netboot.com/netboot.rom allow you to boot your FreeBSD machine over the network and run FreeBSD without having a disk on your client. Under 2.0 it is now possible to have local swap. Swapping over NFS is also still supported. Supported Ethernet cards include: Western Digital/SMC 8003, 8013, 8216 and compatibles; NE1000/NE2000 and compatibles (requires recompile) Setup Instructions Find a machine that will be your server. This machine will require enough disk space to hold the FreeBSD 2.0 binaries and have bootp, tftp and NFS services available. Tested machines: HP-UX HP9000/8xx running HP-UX 9.04 or later (pre 9.04 doesn't work) Solaris Sun/Solaris 2.3. (you may need to get bootp) Set up a bootp server to provide the client with IP, gateway, netmask. diskless:\ :ht=ether:\ :ha=0000c01f848a:\ :sm=255.255.255.0:\ :hn:\ :ds=192.1.2.3:\ :ip=192.1.2.4:\ :gw=192.1.2.5:\ :vm=rfc1048: TFTP bootp Set up a TFTP server (on same machine as bootp server) to provide booting information to client. The name of this file is cfg.X.X.X.X (or /tftpboot/cfg.X.X.X.X, it will try both) where X.X.X.X is the IP address of the client. The contents of this file can be any valid netboot commands. Under 2.0, netboot has the following commands: help print help list ip print/set client's IP address server print/set bootp/tftp server address netmask print/set netmask hostname name print/set hostname kernel print/set kernel name rootfs print/set root filesystem swapfs print/set swap filesystem swapsize set diskless swapsize in KBytes diskboot boot from disk autoboot continue boot process trans | turn transceiver on|off flags set boot flags A typical completely diskless cfg file might contain: rootfs 192.1.2.3:/rootfs/myclient swapfs 192.1.2.3:/swapfs swapsize 20000 hostname myclient.mydomain A cfg file for a machine with local swap might contain: rootfs 192.1.2.3:/rootfs/myclient hostname myclient.mydomain Ensure that your NFS server has exported the root (and swap if applicable) filesystems to your client, and that the client has root access to these filesystems A typical /etc/exports file on FreeBSD might look like: /rootfs/myclient -maproot=0:0 myclient.mydomain /swapfs -maproot=0:0 myclient.mydomain And on HP-UX: /rootfs/myclient -root=myclient.mydomain /swapfs -root=myclient.mydomain - NFSswapping over + + NFS + swapping over + If you are swapping over NFS (completely diskless configuration) create a swap file for your client using dd. If your swapfs command has the arguments /swapfs and the size 20000 as in the example above, the swapfile for myclient will be called /swapfs/swap.X.X.X.X where X.X.X.X is the client's IP addr, e.g.: &prompt.root; dd if=/dev/zero of=/swapfs/swap.192.1.2.4 bs=1k count=20000 Also, the client's swap space might contain sensitive information once swapping starts, so make sure to restrict read and write access to this file to prevent unauthorized access: &prompt.root; chmod 0600 /swapfs/swap.192.1.2.4 Unpack the root filesystem in the directory the client will use for its root filesystem (/rootfs/myclient in the example above). On HP-UX systems: The server should be running HP-UX 9.04 or later for HP9000/800 series machines. Prior versions do not allow the creation of device files over NFS. When extracting /dev in /rootfs/myclient, beware that some systems (HPUX) will not create device files that FreeBSD is happy with. You may have to go to single user mode on the first bootup (press control-c during the bootup phase), cd /dev and do a sh ./MAKEDEV all from the client to fix this. Run netboot.com on the client or make an EPROM from the netboot.rom file Using Shared <filename>/</filename> and <filename>/usr</filename> filesystems Although this is not an officially sanctioned or supported way of doing this, some people report that it works quite well. If anyone has any suggestions on how to do this cleanly, please tell &a.doc;. Compiling netboot for specific setups Netboot can be compiled to support NE1000/2000 cards by changing the configuration in /sys/i386/boot/netboot/Makefile. See the comments at the top of this file. ISDN A good resource for information on ISDN technology and hardware is Dan Kegel's ISDN Page. A quick simple road map to ISDN follows: If you live in Europe you might want to investigate the ISDN card section. If you are planning to use ISDN primarily to connect to the Internet with an Internet Provider on a dial-up non-dedicated basis, you might look into Terminal Adapters. This will give you the most flexibility, with the fewest problems, if you change providers. If you are connecting two LANs together, or connecting to the Internet with a dedicated ISDN connection, you might consider the stand alone router/bridge option. Cost is a significant factor in determining what solution you will choose. The following options are listed from least expensive to most expensive. ISDN Cards Contributed by &a.hm;. - ISDNcards + + ISDN + cards + This section is really only relevant to ISDN users in countries where the DSS1/Q.931 ISDN standard is supported. Some growing number of PC ISDN cards are supported under FreeBSD 2.2.x and up by the isdn4bsd driver package. It is still under development but the reports show that it is successfully used all over Europe. isdn4bsd The latest isdn4bsd version is available from ftp://isdn4bsd@ftp.consol.de/pub/, the main isdn4bsd ftp site (you have to log in as user isdn4bsd , give your mail address as the password and change to the pub directory. Anonymous ftp as user ftp or anonymous will not give the desired result). Isdn4bsd allows you to connect to other ISDN routers using either IP over raw HDLC or by using synchronous PPP. A telephone answering machine application is also available. Many ISDN PC cards are supported, mostly the ones with a Siemens ISDN chipset (ISAC/HSCX), support for other chipsets (from Motorola, Cologne Chip Designs) is currently under development. For an up-to-date list of supported cards, please have a look at the README file. In case you are interested in adding support for a different ISDN protocol, a currently unsupported ISDN PC card or otherwise enhancing isdn4bsd, please get in touch with hm@kts.org. A majordomo maintained mailing list is available. To join the list, send mail to &a.majordomo; and specify: subscribe freebsd-isdn in the body of your message. ISDN Terminal Adapters Terminal adapters(TA), are to ISDN what modems are to regular phone lines. modem Most TA's use the standard hayes modem AT command set, and can be used as a drop in replacement for a modem. A TA will operate basically the same as a modem except connection and throughput speeds will be much faster than your old modem. You will need to configure PPP exactly the same as for a modem setup. Make sure you set your serial speed as high as possible. PPP The main advantage of using a TA to connect to an Internet Provider is that you can do Dynamic PPP. As IP address space becomes more and more scarce, most providers are not willing to provide you with a static IP anymore. Most stand-alone routers are not able to accommodate dynamic IP allocation. TA's completely rely on the PPP daemon that you are running for their features and stability of connection. This allows you to upgrade easily from using a modem to ISDN on a FreeBSD machine, if you already have PPP setup. However, at the same time any problems you experienced with the PPP program and are going to persist. If you want maximum stability, use the kernel PPP option, not the user-land iijPPP. The following TA's are know to work with FreeBSD. Motorola BitSurfer and Bitsurfer Pro Adtran Most other TA's will probably work as well, TA vendors try to make sure their product can accept most of the standard modem AT command set. The real problem with external TA's is like modems you need a good serial card in your computer. You should read the serial ports section in the handbook for a detailed understanding of serial devices, and the differences between asynchronous and synchronous serial ports. A TA running off a standard PC serial port (asynchronous) limits you to 115.2Kbs, even though you have a 128Kbs connection. To fully utilize the 128Kbs that ISDN is capable of, you must move the TA to a synchronous serial card. Do not be fooled into buying an internal TA and thinking you have avoided the synchronous/asynchronous issue. Internal TA's simply have a standard PC serial port chip built into them. All this will do, is save you having to buy another serial cable, and find another empty electrical socket. A synchronous card with a TA is at least as fast as a stand-alone router, and with a simple 386 FreeBSD box driving it, probably more flexible. The choice of sync/TA v.s. stand-alone router is largely a religious issue. There has been some discussion of this in the mailing lists. I suggest you search the archives for the complete discussion. Stand-alone ISDN Bridges/Routers - ISDNstand-alone bridges/routers + + ISDN + stand-alone bridges/routers + ISDN bridges or routers are not at all specific to FreeBSD or any other operating system. For a more complete description of routing and bridging technology, please refer to a Networking reference book. In the context of this page, the terms router and bridge will be used interchangeably. As the cost of low end ISDN routers/bridges comes down, it will likely become a more and more popular choice. An ISDN router is a small box that plugs directly into your local Ethernet network(or card), and manages its own connection to the other bridge/router. It has all the software to do PPP and other protocols built in. A router will allow you much faster throughput that a standard TA, since it will be using a full synchronous ISDN connection. The main problem with ISDN routers and bridges is that interoperability between manufacturers can still be a problem. If you are planning to connect to an Internet provider, you should discuss your needs with them. If you are planning to connect two LAN segments together, ie: home LAN to the office LAN, this is the simplest lowest maintenance solution. Since you are buying the equipment for both sides of the connection you can be assured that the link will work. For example to connect a home computer or branch office network to a head office network the following setup could be used. Branch office or Home network 10 base 2 Network uses a bus based topology with 10 base 2 Ethernet ("thinnet"). Connect router to network cable with AUI/10BT transceiver, if necessary. ---Sun workstation | ---FreeBSD box | ---Windows 95 (Do not admit to owning it) | Stand-alone router | ISDN BRI line 10 Base 2 Ethernet If your home/branch office is only one computer you can use a twisted pair crossover cable to connect to the stand-alone router directly. Head office or other LAN 10 base T Network uses a star topology with 10 base T Ethernet ("Twisted Pair"). -------Novell Server | H | | ---Sun | | | U ---FreeBSD | | | ---Windows 95 | B | |___---Stand-alone router | ISDN BRI line ISDN Network Diagram One large advantage of most routers/bridges is that they allow you to have 2 separate independent PPP connections to 2 separate sites at the same time. This is not supported on most TA's, except for specific(expensive) models that have two serial ports. Do not confuse this with channel bonding, MPP etc. This can be very useful feature, for example if you have an dedicated ISDN connection at your office and would like to tap into it, but don't want to get another ISDN line at work. A router at the office location can manage a dedicated B channel connection (64Kbs) to the internet, as well as a use the other B channel for a separate data connection. The second B channel can be used for dial-in, dial-out or dynamically bond(MPP etc.) with the first B channel for more bandwidth. IPX/SPX An Ethernet bridge will also allow you to transmit more than just IP traffic, you can also send IPX/SPX or whatever other protocols you use. NIS/YP Written by &a.unfurl;, 21 January 2000, enhanced with parts and comments from Eric Ogren eogren@earthlink.net and Udo Erdelhoff ue@nathan.ruhr.de in June 2000. What is it? NIS Solaris HP-UX AIX Linux NetBSD OpenBSD NIS, which stands for Network Information Services, was developed by Sun Microsystems to centralize administration of Unix (originally SunOS) systems. It has now essentially become an industry standard; all major Unices (Solaris, HP-UX, AIX, Linux, NetBSD, OpenBSD, FreeBSD, etc) support NIS. yellow pages (see NIS) NIS was formerly known as Yellow Pages (or yp), but due to copyright violations, Sun was forced to change the name. - NISdomains + + NIS + domains + It is a RPC-based client/server system that allows a group of machines within an NIS domain to share a common set of configuration files. This permits a system administrator to set up NIS client systems with only minimal configuration data and add, remove or modify configuration data from a single location. Windows NT It is similar to Windows NT's domain system; although the internal implementation of the two aren't at all similar, the basic functionality can be compared. Terms/processes you should know There are several terms and several important user processes that you will come across when attempting to implement NIS on FreeBSD, whether you are trying to create an NIS server or act an NIS client: The NIS domainname. An NIS master server and all of its clients (including its slave servers) have a NIS domainname. Similar to an NT domain name, the NIS domainname does not have anything to do with DNS. portmap portmap. portmap must be running in order to enable RPC (Remote Procedure Call, a network protocol used by NIS). If portmap is not running, it will be impossible to run an NIS server, or to act as an NIS client. ypbind. ypbind “binds” an NIS client to its NIS server. It will take the NIS domainname from the system, and using RPC, connect to the server. ypbind is the core of client-server communication in an NIS environment; if ypbind dies on a client machine, it will not be able to access the NIS server. ypserv. ypserv, which should only be running on NIS servers, is the NIS server process itself. If ypserv dies, then the server will no longer be able to respond to NIS requests (hopefully, there is a slave server to take over for it). There are some implementations of NIS (but not the FreeBSD one), that don't try to reconnect to another server if the server it used before dies. Often, the only thing that helps in this case is to restart the server process (or even the whole server) or the ypbind process on the client. rpc.yppasswdd. rpc.yppasswdd, another process that should only be running on NIS master servers, is a daemon that will allow NIS clients to change their NIS passwords. If this daemon is not running, users will have to login to the NIS master server and change their passwords there. How does it work? There are three types of hosts in an NIS environment; master servers, slave servers, and clients. Servers act as a central repository for host configuration information. Master servers hold the authoritative copy of this information, while slave servers mirror this information for redundancy. Clients rely on the servers to provide this information to them. Information in many files can be shared in this manner. The master.passwd, group, and hosts files are commonly shared via NIS. Whenever a process on a client needs information that would normally be found in these files locally, it makes a query to the server it is bound to, to get this information. Machine types - NISmaster server + + NIS + master server + A NIS master server. This server, analogous to a Windows NT primary domain controller, maintains the files used by all of the NIS clients. The passwd, group, and other various files used by the NIS clients live on the master server. It is possible for one machine to be an NIS master server for more than one NIS domain. However, this will not be covered in this introduction, which assumes a relatively small-scale NIS environment. - NISslave server + + NIS + slave server + NIS slave servers. Similar to NT's backup domain controllers, NIS slave servers maintain copies of the NIS master's data files. NIS slave servers provide the redundancy, which is needed in important environments. They also help to balance the load of the master server: NIS Clients always attach to the NIS server whose response they get first, and this includes slave-server-replies. - NISclient + + NIS + client + NIS clients. NIS clients, like most NT workstations, authenticate against the NIS server (or the NT domain controller in the NT Workstation case) to log on. Using NIS/YP This section will deal with setting up a sample NIS environment. This section assumes that you are running FreeBSD 3.3 or later. The instructions given here will probably work for any version of FreeBSD greater than 3.0, but there are no guarantees that this is true. Planning Let's assume that you are the administrator of a small university lab. This lab, which consists of 15 FreeBSD machines, currently has no centralized point of administration; each machine has its own /etc/passwd and /etc/master.passwd. These files are kept in sync with each other only through manual intervention; currently, when you add a user to the lab, you must run adduser on all 15 machines. Clearly, this has to change, so you have decided to convert the lab to use NIS, using two of the machines as servers. Therefore, the configuration of the lab now looks something like: Machine name IP address Machine role ellington 10.0.0.2 NIS master coltrane 10.0.0.3 NIS slave basie 10.0.0.4 Faculty workstation bird 10.0.0.5 Client machine cli[1-11] 10.0.0.[6-17] Other client machines If you are setting up a NIS scheme for the first time, it is a good idea to think through how you want to go about it. No matter what the size of your network, there are a few decisions that need to be made. Choosing a NIS Domain Name - NISdomainname + + NIS + domainname + This might not be the domainname that you are used to. It is more accurately called the NIS domainname. When a client broadcasts its requests for info, it includes the name of the NIS domain that it is part of. This is how multiple servers on one network can tell which server should answer which request. Think of the NIS domainname as the name for a group of hosts that are related in some way. Some organizations choose to use their Internet domainname for their NIS domainname. This is not recommended as it can cause confusion when trying to debug network problems. The NIS domainname should be unique within your network and it is helpful if it describes the group of machines it represents. For example, the Art department at Acme Inc. might be in the "acme-art" NIS domain. For this example, assume you have chosen the name test-domain. SunOS However, some operating systems (notably SunOS) use their NIS domain name as their Internet domain name. If one or more machines on your network have this restriction, you must use the Internet domain name as your NIS domain name. Physical Server Requirements There are several things to keep in mind when choosing a machine to use as a NIS server. One of the unfortunate things about NIS is the level of dependency the clients have on the server. If a client cannot contact the server for its NIS domain, very often the machine becomes unusable. The lack of user and group information causes most systems to temporarily freeze up. With this in mind you should make sure to choose a machine that won't be prone to being rebooted regularly, or one that might be used for development. The NIS server should ideally be a stand alone machine whose sole purpose in life is to be an NIS server. If you have a network that is not very heavily used, it is acceptable to put the NIS server on a machine running other services, just keep in mind that if the NIS server becomes unavailable, it will affect all of your NIS clients adversely. NIS Servers The canonical copies of all NIS information are stored on a single machine called the NIS master server. The databases used to store the information are called NIS maps. In FreeBSD, these maps are stored in /var/yp/[domainname] where [domainname] is the name of the NIS domain being served. A single NIS server can support several domains at once, therefore it is possible to have several such directories, one for each supported domain. Each domain will have its own independent set of maps. NIS master and slave servers handle all NIS requests with the ypserv daemon. Ypserv is responsible for receiving incoming requests from NIS clients, translating the requested domain and map name to a path to the corresponding database file and transmitting data from the database back to the client. Setting up a NIS master server - NISserver configuration + + NIS + server configuration + Setting up a master NIS server can be relatively straight forward, depending on your needs. FreeBSD comes with support for NIS out-of-the-box. All you need is to add the following lines to /etc/rc.conf, and FreeBSD will do the rest for you. nisdomainname="test-domain" This line will set the NIS domainname to test-domain upon network setup (e.g. after reboot). nis_server_enable="YES" This will tell FreeBSD to start up the NIS server processes when the networking is next brought up. nis_yppasswdd_enable="YES" This will enable the rpc.yppasswdd daemon, which, as mentioned above, will allow users to change their NIS password from a client machine. Now, all you have to do is to run the command /etc/netstart as superuser. It will setup everything for you, using the values you defined in /etc/rc.conf. Initializing the NIS maps NIS maps The NIS maps are database files, that are kept in the /var/yp directory. They are generated from configuration files in the /etc directory of the NIS master, with one exception: the /etc/master.passwd file. This is for a good reason; you don't want to propagate passwords to your root and other administrative accounts to all the servers in the NIS domain. Therefore, before we initialize the NIS maps, you should: &prompt.root; cp /etc/master.passwd /var/yp/master.passwd &prompt.root; cd /var/yp &prompt.root; vi master.passwd You should remove all entries regarding system accounts (bin, tty, kmem, games, etc), as well as any accounts that you don't want to be propagated to the NIS clients (for example root and any other UID 0 (superuser) accounts). Make sure the /var/yp/master.passwd is neither group nor world readable (mode 600)! Use the chmod command, if appropriate. Tru64 Unix When you have finished, it's time to initialize the NIS maps! FreeBSD includes a script named ypinit to do this for you (see its man page for more information). Note that this script is available on most UNIX OSs, but not on all. On Digital Unix/Compaq Tru64 Unix it is called ypsetup. Because we are generating maps for an NIS master, we are going to pass the option to ypinit. To generate the NIS maps, assuming you already performed the steps above, run: ellington&prompt.root; ypinit -m test-domain Server Type: MASTER Domain: test-domain Creating an YP server will require that you answer a few questions. Questions will all be asked at the beginning of the procedure. Do you want this procedure to quit on non-fatal errors? [y/n: n] n Ok, please remember to go back and redo manually whatever fails. If you don't, something might not work. At this point, we have to construct a list of this domains YP servers. rod.darktech.org is already known as master server. Please continue to add any slave servers, one per line. When you are done with the list, type a <control D>. master server : ellington next host to add: coltrane next host to add: ^D The current list of NIS servers looks like this: ellington coltrane Is this correct? [y/n: y] y [..output from map generation..] NIS Map update completed. ellington has been setup as an YP master server without any errors. ypinit should have created /var/yp/Makefile from /var/yp/Makefile.dist. When created, this file assumes that you are operating in a single server NIS environment with only FreeBSD machines. Since test-domain has a slave server as well, you must edit /var/yp/Makefile: ellington&prompt.root; vi /var/yp/Makefile You should comment out the line that says `NOPUSH = "True"' (if it is not commented out already). Setting up a NIS slave server - NISconfiguring a - slave server + + NIS + configuring a slave server + Setting up an NIS slave server is even more simple than setting up the master. Log on to the slave server and edit the file /etc/rc.conf as you did before. The only difference is that we now must use the option when running ypinit. The option requires the name of the NIS master be passed to it as well, so our command line looks like: coltrane&prompt.root; ypinit -s ellington test-domain Server Type: SLAVE Domain: test-domain Master: ellington Creating an YP server will require that you answer a few questions. Questions will all be asked at the beginning of the procedure. Do you want this procedure to quit on non-fatal errors? [y/n: n] n Ok, please remember to go back and redo manually whatever fails. If you don't, something might not work. There will be no further questions. The remainder of the procedure should take a few minutes, to copy the databases from ellington. Transferring netgroup... ypxfr: Exiting: Map successfully transferred Transferring netgroup.byuser... ypxfr: Exiting: Map successfully transferred Transferring netgroup.byhost... ypxfr: Exiting: Map successfully transferred Transferring master.passwd.byuid... ypxfr: Exiting: Map successfully transferred Transferring passwd.byuid... ypxfr: Exiting: Map successfully transferred Transferring passwd.byname... ypxfr: Exiting: Map successfully transferred Transferring group.bygid... ypxfr: Exiting: Map successfully transferred Transferring group.byname... ypxfr: Exiting: Map successfully transferred Transferring services.byname... ypxfr: Exiting: Map successfully transferred Transferring rpc.bynumber... ypxfr: Exiting: Map successfully transferred Transferring rpc.byname... ypxfr: Exiting: Map successfully transferred Transferring protocols.byname... ypxfr: Exiting: Map successfully transferred Transferring master.passwd.byname... ypxfr: Exiting: Map successfully transferred Transferring networks.byname... ypxfr: Exiting: Map successfully transferred Transferring networks.byaddr... ypxfr: Exiting: Map successfully transferred Transferring netid.byname... ypxfr: Exiting: Map successfully transferred Transferring hosts.byaddr... ypxfr: Exiting: Map successfully transferred Transferring protocols.bynumber... ypxfr: Exiting: Map successfully transferred Transferring ypservers... ypxfr: Exiting: Map successfully transferred Transferring hosts.byname... ypxfr: Exiting: Map successfully transferred coltrane has been setup as an YP slave server without any errors. Don't forget to update map ypservers on ellington. You should now have a directory called /var/yp/test-domain. Copies of the NIS master server's maps should be in this directory. You will need to make sure that these stay updated. The following /etc/crontab entries on your slave servers should do the job: 20 * * * * root /usr/libexec/ypxfr passwd.byname 21 * * * * root /usr/libexec/ypxfr passwd.byuid These two lines force the slave to sync its maps with the maps on the master server. Although this is not mandatory, because the master server tries to make sure any changes to its NIS maps are communicated to its slaves, the password information is so vital to systems that depend on the server, that it is a good idea to force the updates. This is more important on busy networks where map updates might not always complete. Now, run the command /etc/netstart on the slave server as well, which again starts the NIS server. NIS Clients An NIS client establishes what is called a binding to a particular NIS server using the ypbind daemon. ypbind checks the system's default domain (as set by the domainname command), and begins broadcasting RPC requests on the local network. These requests specify the name of the domain for which ypbind is attempting to establish a binding. If a server that has been configured to serve the requested domain receives one of the broadcasts, it will respond to ypbind, which will record the server's address. If there are several servers available (a master and several slaves, for example), ypbind will use the address of the first one to respond. From that point on, the client system will direct all of its NIS requests to that server. Ypbind will occasionally ping the server to make sure it is still up and running. If it fails to receive a reply to one of its pings within a reasonable amount of time, ypbind will mark the domain as unbound and begin broadcasting again in the hopes of locating another server. Setting up an NIS client - NISclient configuration + + NIS + client configuration + Setting up a FreeBSD machine to be a NIS client is fairly straightforward. Edit the file /etc/rc.conf and add the following lines in order to set the NIS domainname and start ypbind upon network startup: nisdomainname="test-domain" nis_client_enable="YES" To import all possible password entries from the NIS server, add this line to your /etc/master.passwd file, using vipw: +::::::::: This line will afford anyone with a valid account in the NIS server's password maps an account. There are many ways to configure your NIS client by changing this line. See the netgroups part below for more information. For more detailed reading see O'Reilly's book on Managing NFS and NIS. To import all possible group entries from the NIS server, add this line to your /etc/group file: +:*:: After completing these steps, you should be able to run ypcat passwd and see the NIS server's passwd map. NIS Security In general, any remote user can issue an RPC to ypserv and retrieve the contents of your NIS maps, provided the remote user knows your domainname. To prevent such unauthorized transactions, ypserv supports a feature called securenets which can be used to restrict access to a given set of hosts. At startup, ypserv will attempt to load the securenets information from a file called /var/yp/securenets. This path varies depending on the path specified with the option. This file contains entries that consist of a network specification and a network mask separated by white space. Lines starting with # are considered to be comments. A sample securenets file might look like this: # allow connections from local host -- mandatory 127.0.0.1 255.255.255.255 # allow connections from any host # on the 192.168.128.0 network 192.168.128.0 255.255.255.0 # allow connections from any host # between 10.0.0.0 to 10.0.15.255 # this includes the machines in the testlab 10.0.0.0 255.255.240.0 If ypserv receives a request from an address that matches one of these rules, it will process the request normally. If the address fails to match a rule, the request will be ignored and a warning message will be logged. If the /var/yp/securenets file does not exist, ypserv will allow connections from any host. The ypserv program also has support for Wietse Venema's tcpwrapper package. This allows the administrator to use the tcpwrapper configuration files for access control instead of /var/yp/securenets. While both of these access control mechanisms provide some security, they, like the privileged port test, are vulnerable to IP spoofing attacks. All NIS-related traffic should be blocked at your firewall. Servers using /var/yp/securenets may fail to serve legitimate NIS clients with archaic TCP/IP implementations. Some of these implementations set all host bits to zero when doing broadcasts and/or fail to observe the subnet mask when calculating the broadcast address. While some of these problems can be fixed by changing the client configuration, other problems may force the retirement of the client systems in question or the abandonment of /var/yp/securenets. Using /var/yp/securenets on a server with such an archaic implementation of TCP/IP is a really bad idea and will lead to loss of NIS functionality for large parts of your network. tcpwrapper The use of the tcpwrapper package increases the latency of your NIS server. The additional delay may be long enough to cause timeouts in client programs, especially in busy networks or with slow NIS servers. If one or more of your client systems suffers from these symptoms, you should convert the client systems in question into NIS slave servers and force them to bind to themselves. Barring some users from logging on In our lab, there is a machine basie that is supposed to be a faculty only workstation. We don't want to take this machine out of the NIS domain, yet the passwd file on the master NIS server contains accounts for both faculty and students. What can we do? There is a way to bar specific users from logging on to a machine, even if they are present in the NIS database. To do this, all you must do is add -username to the end of the /etc/master.passwd file on the client machine, where username is the username of the user you wish to bar from logging in. This should preferably be done using vipw, since vipw will sanity check your changes to /etc/master.passwd, as well as automatically rebuild the password database when you finish editing. For example, if we wanted to bar user bill from logging on to basie we would: basie&prompt.root; vipw [add -bill to the end, exit] vipw: rebuilding the database... vipw: done basie&prompt.root; cat /etc/master.passwd root:[password]:0:0::0:0:The super-user:/root:/bin/csh toor:[password]:0:0::0:0:The other super-user:/root:/bin/sh daemon:*:1:1::0:0:Owner of many system processes:/root:/sbin/nologin operator:*:2:5::0:0:System &:/:/sbin/nologin bin:*:3:7::0:0:Binaries Commands and Source,,,:/:/sbin/nologin tty:*:4:65533::0:0:Tty Sandbox:/:/sbin/nologin kmem:*:5:65533::0:0:KMem Sandbox:/:/sbin/nologin games:*:7:13::0:0:Games pseudo-user:/usr/games:/sbin/nologin news:*:8:8::0:0:News Subsystem:/:/sbin/nologin man:*:9:9::0:0:Mister Man Pages:/usr/share/man:/sbin/nologin bind:*:53:53::0:0:Bind Sandbox:/:/sbin/nologin uucp:*:66:66::0:0:UUCP pseudo-user:/var/spool/uucppublic:/usr/libexec/uucp/uucico xten:*:67:67::0:0:X-10 daemon:/usr/local/xten:/sbin/nologin pop:*:68:6::0:0:Post Office Owner:/nonexistent:/sbin/nologin nobody:*:65534:65534::0:0:Unprivileged user:/nonexistent:/sbin/nologin +::::::::: -bill basie&prompt.root; Using netgroups netgroups The netgroups part was contributed by Udo Erdelhoff ue@nathan.ruhr.de in July 2000. The method shown in the previous chapter works reasonably well if you need special rules for a very small number of users and/or machines. On larger networks, you will forget to bar some users from logging onto sensitive machines, or you may even have to modify each machine separately, thus losing the main benefit of NIS, centralized administration. The NIS developers' solution for this problem is called netgroups. Their purpose and semantics can be compared to the normal groups used by Unix file systems. The main differences are the lack of a numeric id and the ability to define a netgroup by including both user accounts and other netgroups. Netgroups were developed to handle large, complex networks with hundreds of users and machines. On one hand, this is a Good Thing if you are forced to deal with such a situation. On the other hand, this complexity makes it almost impossible to explain netgroups with really simple examples. The example used in the remainder of this chapter demonstrates this problem. Let us assume that your successful introduction of NIS in your laboratory caught your superiors' interest. Your next job is to extend your NIS domain to cover some of the other machines on campus. The two tables contain the names of the new users and new machines as well as brief descriptions of them. User Name(s) Description alpha, beta Normal employees of the IT department charlie, delta The new apprentices of the IT department echo, foxtrott, golf, ... Ordinary employees able, baker, ... The current interns Machine Name(s) Description war, death, famine, pollution Your most important servers. Only the IT employees are allowed to log onto these machines. pride, greed, envy, wrath, lust, sloth Less important servers. All members of the IT department are allowed to login onto these machines. one, two, three, four, ... Ordinary workstations. Only the real employees are allowed to use these machines. trashcan A very old machine without any critical data. Even the intern is allowed to use this box. If you tried to implement these restrictions by separately blocking each user, you would have to add one -user line to each system's passwd for each user who is not allowed to login onto that system. If you forget just one entry, you could be in trouble. It may be feasible to do this correctly during the initial setup, however you will eventually forget to add the lines for new users during day-to-day operations. After all, Murphy was an optimist. Handling this situation with netgroups offers several advantages. Each user need not be handled separately; you assign a user to one or more netgroups and allow or forbid logins for all members of the netgroup. If you add a new machine, you will only have to define login restrictions for netgroups. If a new user is added, you will only have to add the user to one or more netgroups. Those changes are independent of each other; no more for each combination of user and machine do... If your NIS setup is planned carefully, you will only have to modify exactly one central configuration file to grant or deny access to machines. The first step is the initialization of the NIS map netgroup. FreeBSD's ypinit does not create this map by default, but its NIS implementation will support it once it has been created. To create an empty map, simply type ellington&prompt.root; vi /var/yp/netgroup and start adding content. For our example, we need at least four netgroups: IT employees, IT apprentices, normal employees and interns. IT_EMP (,alpha,test-domain) (,beta,test-domain) IT_APP (,charlie,test-domain) (,delta,test-domain) USERS (,echo,test-domain) (,foxtrott,test-domain) \ (,golf,test-domain) INTERNS (,able,test-domain) (,baker,test-domain) IT_EMP, IT_APP etc. are the names of the netgroups. Each bracketed group adds one or more user accounts to it. The three fields inside a group are: The name of the host(s) where the following items are valid. If you do not specify a hostname, the entry is valid on all hosts. If you do specify a hostname, you will enter a realm of darkness, horror and utter confusion. The name of the account that belongs to this netgroup. The NIS domain for the account. You can import accounts from other NIS domains into your netgroup if you are one of unlucky fellows with more than one NIS domain. Each of these fields can contain wildcards. See &man.netgroup.5; for details. netgroups Netgroup names longer than 8 characters should not be used, especially if you have machines running other operating systems within your NIS domain. The names are case sensitive; using capital letters for your netgroup names is an easy way to distinguish between user, machine and netgroup names. Some NIS clients (other than FreeBSD) cannot handle netgroups with a large number of entries. For example, some older versions of SunOS start to cause trouble if a netgroup contains more than 15 entries. You can circumvent this limit by creating several sub-netgroups with 15 users or less and a real netgroup that consists of the sub-netgroups: BIGGRP1 (,joe1,domain) (,joe2,domain) (,joe3,domain) [...] BIGGRP2 (,joe16,domain) (,joe17,domain) [...] BIGGRP3 (,joe31,domain) (,joe32,domain) BIGGROUP BIGGRP1 BIGGRP2 BIGGRP3 You can repeat this process if you need more than 225 users within a single netgroup. Activating and distributing your new NIS map is easy: ellington&prompt.root; cd /var/yp ellington&prompt.root; make This will generate the three NIS maps netgroup, netgroup.byhost and netgroup.byuser. Use &man.ypcat.1; to check if your new NIS maps are available: ellington&prompt.user; ypcat -k netgroup ellington&prompt.user; ypcat -k netgroup.byhost ellington&prompt.user; ypcat -k netgroup.byuser The output of the first command should resemble the contents of /var/yp/netgroup. The second command will not produce output if you have not specified host-specific netgroups. The third command can be used to get the list of netgroups for a user. The client setup is quite simple. To configure the server war, you only have to start &man.vipw.8; and replace the line +::::::::: with +@IT_EMP::::::::: Now, only the data for the users defined in the netgroup IT_EMP is imported into war's password database and only these users are allowed to login. Unfortunately, this limitation also applies to the ~ function of the shell and all routines converting between user names and numerical user ids. In other words, cd ~user will not work, ls -l will show the numerical id instead of the username and find . -user joe -print will fail with No such user. To fix this, you will have to import all user entries without allowing them to login onto your servers. This can be achieved by adding another line to /etc/master.passwd. This line should contain +:::::::::/sbin/nologin, meaning Import all entries but replace the shell with /sbin/nologin in the imported entries. You can replace any field in the passwd entry by placing a default value in your /etc/master.passwd. Make sure that the line +:::::::::/sbin/nologin is placed after +@IT_EMP:::::::::. Otherwise, all user accounts imported from NIS will have /sbin/nologin as their login shell. After this change, you will only have to change one NIS map if a new employee joins the IT department. You could use a similar approach for the less important servers by replacing the old +::::::::: in their local version of /etc/master.passwd with something like this: +@IT_EMP::::::::: +@IT_APP::::::::: +:::::::::/sbin/nologin The corresponding lines for the normal workstations could be: +@IT_EMP::::::::: +@USERS::::::::: +:::::::::/sbin/nologin And everything would be fine until there is a policy change a few weeks later: The IT department starts hiring interns. The IT interns are allowed to use the normal workstations and the less important servers; and the IT apprentices are allowed to login onto the main servers. You add a new netgroup IT_INTERN, add the new IT interns to this netgroup and start to change the config on each and every machine... As the old saying goes: Errors in centralized planning lead to global mess. NIS' ability to create netgroups from other netgroups can be used to prevent situations like these. One possibility is the creation of role-based netgroups. For example, you could create a netgroup called BIGSRV to define the login restrictions for the important servers, another netgroup called SMALLSRV for the less important servers and a third netgroup called USERBOX for the normal workstations. Each of these netgroups contains the netgroups that are allowed to login onto these machines. The new entries for your NIS map netgroup should look like this: BIGSRV IT_EMP IT_APP SMALLSRV IT_EMP IT_APP ITINTERN USERBOX IT_EMP ITINTERN USERS This method of defining login restrictions works reasonably well if you can define groups of machines with identical restrictions. Unfortunately, this is the exception and not the rule. Most of the time, you will need the ability to define login restrictions on a per-machine basis. Machine-specific netgroup definitions are the other possibility to deal with the policy change outlined above. In this scenario, the /etc/master.passwd of each box contains two lines starting with ``+''. The first of them adds a netgroup with the accounts allowed to login onto this machine, the second one adds all other accounts with /sbin/nologin as shell. It is a good idea to use the ALL-CAPS version of the machine name as the name of the netgroup. In other words, the lines should look like this: +@BOXNAME::::::::: +:::::::::/sbin/nologin Once you have completed this task for all your machines, you will not have to modify the local versions of /etc/master.passwd ever again. All further changes can be handled by modifying the NIS map. Here is an example of a possible netgroup map for this scenario with some additional goodies. # Define groups of users first IT_EMP (,alpha,test-domain) (,beta,test-domain) IT_APP (,charlie,test-domain) (,delta,test-domain) DEPT1 (,echo,test-domain) (,foxtrott,test-domain) DEPT2 (,golf,test-domain) (,hotel,test-domain) DEPT3 (,india,test-domain) (,juliet,test-domain) ITINTERN (,kilo,test-domain) (,lima,test-domain) D_INTERNS (,able,test-domain) (,baker,test-domain) # # Now, define some groups based on roles USERS DEPT1 DEPT2 DEPT3 BIGSRV IT_EMP IT_APP SMALLSRV IT_EMP IT_APP ITINTERN USERBOX IT_EMP ITINTERN USERS # # And a groups for a special tasks # Allow echo and golf to access our anti-virus-machine SECURITY IT_EMP (,echo,test-domain) (,golf,test-domain) # # machine-based netgroups # Our main servers WAR BIGSRV FAMINE BIGSRV # User india needs access to this server POLLUTION BIGSRV (,india,test-domain) # # This one is really important and needs more access restrictions DEATH IT_EMP # # The anti-virus-machine mentioned above ONE SECURITY # # Restrict a machine to a single user TWO (,hotel,test-domain) # [...more groups to follow] If you are using some kind of database to manage your user accounts, you should be able to create the first part of the map with your database's report tools. This way, new users will automatically have access to the boxes. One last word of caution: It may not always be advisable to use machine-based netgroups. If you are deploying a couple dozen or even hundreds of identical machines for student labs, you should use role-based netgroups instead of machine-based netgroups to keep the size of the NIS map within reasonable limits. Important things to remember There are still a couple of things that you will need to do differently now that you are in an NIS environment. Every time you wish to add a user to the lab, you must add it to the master NIS server only, and you must remember to rebuild the NIS maps. If you forget to do this, the new user will not be able to login anywhere except on the NIS master. For example, if we needed to add a new user “jsmith” to the lab, we would: &prompt.root; pw useradd jsmith &prompt.root; cd /var/yp &prompt.root; make test-domain You could also run adduser jsmith instead of pw useradd jsmith. Keep the administration accounts out of the NIS maps. You don't want to be propagating administrative accounts and passwords to machines that will have users that shouldn't have access to those accounts. Keep the NIS master and slave secure, and minimize their downtime. If somebody either hacks or simply turns off these machines, they have effectively rendered many people without the ability to login to the lab. This is the chief weakness of any centralized administration system, and it is probably the most important weakness. If you do not protect your NIS servers, you will have a lot of angry users! NIS v1 compatibility FreeBSD's ypserv has some support for serving NIS v1 clients. FreeBSD's NIS implementation only uses the NIS v2 protocol, however other implementations include support for the v1 protocol for backwards compatibility with older systems. The ypbind daemons supplied with these systems will try to establish a binding to an NIS v1 server even though they may never actually need it (and they may persist in broadcasting in search of one even after they receive a response from a v2 server). Note that while support for normal client calls is provided, this version of ypserv does not handle v1 map transfer requests; consequently, it can not be used as a master or slave in conjunction with older NIS servers that only support the v1 protocol. Fortunately, there probably are not any such servers still in use today. NIS servers that are also NIS clients Care must be taken when running ypserv in a multi-server domain where the server machines are also NIS clients. It is generally a good idea to force the servers to bind to themselves rather than allowing them to broadcast bind requests and possibly become bound to each other. Strange failure modes can result if one server goes down and others are dependent upon on it. Eventually all the clients will time out and attempt to bind to other servers, but the delay involved can be considerable and the failure mode is still present since the servers might bind to each other all over again. You can force a host to bind to a particular server by running ypbind with the flag. libscrypt v.s. libdescrypt - NIScrypto library + + NIS + crypto library + One of the most common issues that people run into when trying to implement NIS is crypt library compatibility. If your NIS server is using the DES crypt libraries, it will only support clients that are using DES as well. To check which one your server and clients are using look at the symlinks in /usr/lib. If the machine is configured to use the DES libraries, it will look something like this: &prompt.user; ls -l /usr/lib/*crypt* lrwxrwxrwx 1 root wheel 13 Jul 15 08:55 /usr/lib/libcrypt.a@ -> libdescrypt.a lrwxrwxrwx 1 root wheel 14 Jul 15 08:55 /usr/lib/libcrypt.so@ -> libdescrypt.so lrwxrwxrwx 1 root wheel 16 Jul 15 08:55 /usr/lib/libcrypt.so.2@ -> libdescrypt.so.2 lrwxrwxrwx 1 root wheel 15 Jul 15 08:55 /usr/lib/libcrypt_p.a@ -> libdescrypt_p.a -r--r--r-- 1 root wheel 13018 Nov 8 14:27 /usr/lib/libdescrypt.a lrwxr-xr-x 1 root wheel 16 Nov 8 14:27 /usr/lib/libdescrypt.so@ -> libdescrypt.so.2 -r--r--r-- 1 root wheel 12965 Nov 8 14:27 /usr/lib/libdescrypt.so.2 -r--r--r-- 1 root wheel 14750 Nov 8 14:27 /usr/lib/libdescrypt_p.a If the machine is configured to use the standard FreeBSD MD5 crypt libraries they will look something like this: &prompt.user; ls -l /usr/lib/*crypt* lrwxrwxrwx 1 root wheel 13 Jul 15 08:55 /usr/lib/libcrypt.a@ -> libscrypt.a lrwxrwxrwx 1 root wheel 14 Jul 15 08:55 /usr/lib/libcrypt.so@ -> libscrypt.so lrwxrwxrwx 1 root wheel 16 Jul 15 08:55 /usr/lib/libcrypt.so.2@ -> libscrypt.so.2 lrwxrwxrwx 1 root wheel 15 Jul 15 08:55 /usr/lib/libcrypt_p.a@ -> libscrypt_p.a -r--r--r-- 1 root wheel 6194 Nov 8 14:27 /usr/lib/libscrypt.a lrwxr-xr-x 1 root wheel 14 Nov 8 14:27 /usr/lib/libscrypt.so@ -> libscrypt.so.2 -r--r--r-- 1 root wheel 7579 Nov 8 14:27 /usr/lib/libscrypt.so.2 -r--r--r-- 1 root wheel 6684 Nov 8 14:27 /usr/lib/libscrypt_p.a If you have trouble authenticating on an NIS client, this is a pretty good place to start looking for possible problems. If you want to deploy an NIS server for a heterogenous network, you will probably have to use DES on all systems because it is the lowest common standard. DHCP Written by &a.gsutter;, March 2000. What is DHCP? - Dynamic Host Configuration Protocol (DHCP) - Internet Software Consortium (ISC) + + Dynamic Host Configuration Protocol (DHCP) + + + Internet Software Consortium (ISC) + DHCP, the Dynamic Host Configuration Protocol, describes the means by which a system can connect to a network and obtain the necessary information for communication upon that network. FreeBSD uses the ISC (Internet Software Consortium) DHCP implementation, so all implementation-specific information here is for use with the ISC distribution. What This Section Covers This handbook section attempts to describe only the parts of the DHCP system that are integrated with FreeBSD; consequently, the server portions are not described. The DHCP manual pages, in addition to the references below, are useful resources. How it Works UDP When dhclient, the DHCP client, is executed on the client machine, it begins broadcasting requests for configuration information. By default, these requests are on UDP port 68. The server replies on UDP 67, giving the client an IP address and other relevant network information such as netmask, router, and DNS servers. All of this information comes in the form of a DHCP "lease" and is only valid for a certain time (configured by the DHCP server maintainer). In this manner, stale IP addresses for clients no longer connected to the network can be automatically reclaimed. DHCP clients can obtain a great deal of information from the server. An exhaustive list may be found in &man.dhcp-options.5;. FreeBSD Integration FreeBSD fully integrates the ISC DHCP client, dhclient. DHCP client support is provided within both the installer and the base system, obviating the need for detailed knowledge of network configurations on any network that runs a DHCP server. dhclient has been included in all FreeBSD distributions since 3.2. sysinstall DHCP is supported by sysinstall. When configuring a network interface within sysinstall, the first question asked is, "Do you want to try dhcp configuration of this interface?" Answering affirmatively will execute dhclient, and if successful, will fill in the network configuration information automatically. There are two things you must do to have your system use DHCP upon startup: - DHCPrequirements + + DHCP + requirements + Make sure that the bpf device is compiled into your kernel. To do this, add pseudo-device bpf to your kernel configuration file, and rebuild the kernel. For more information about building kernels, see . The bpf device is already part of the GENERIC kernel that is supplied with FreeBSD, so if you don't have a custom kernel, you shouldn't need to create one in order to get DHCP working. For those who are particularly security conscious, you should be warned that bpf is also the device that allows packet sniffers to work correctly (although they still have to be run as root). bpf is required to use DHCP, but if you are very sensitive about security, you probably shouldn't add bpf to your kernel in the expectation that at some point in the future you will be using DHCP. Edit your /etc/rc.conf to include the following: ifconfig_fxp0="DHCP" Be sure to replace fxp0 with the designation for the interface that you wish to dynamically configure. If you are using a different location for dhclient, or if you wish to pass additional flags to dhclient, also include the following (editing as necessary): dhcp_program="/sbin/dhclient" dhcp_flags="" - DHCPserver + + DHCP + server + The DHCP server, dhcpd, is included as part of the isc-dhcp2 port in the ports collection. This port contains the full ISC DHCP distribution, consisting of client, server, relay agent and documentation. Files - DHCPconfiguration files + + DHCP + configuration files + /etc/dhclient.conf dhclient requires a configuration file, /etc/dhclient.conf. Typically the file contains only comments, the defaults being reasonably sane. This configuration file is described by the &man.dhclient.conf.5; man page. /sbin/dhclient dhclient is statically linked and resides in /sbin. The &man.dhclient.8; manual page gives more information about dhclient. /sbin/dhclient-script dhclient-script is the FreeBSD-specific DHCP client configuration script. It is described in &man.dhclient-script.8;, but should not need any user modification to function properly. /var/db/dhclient.leases The DHCP client keeps a database of valid leases in this file, which is written as a log. &man.dhclient.leases.5; gives a slightly longer description. Further Reading The DHCP protocol is fully described in RFC 2131. An informational resource has also been set up at dhcp.org. DNS Contributed by &a.chern;, April 12, 2001. Overview BIND FreeBSD utilizes, by default, a version of BIND (Berkeley Internet Name Domain), which is the most common implementation of the DNS protocol. DNS is the protocol through which names are mapped to IPs, and vice versa. For example, a query for www.freebsd.org will send back a reply for the IP address of The FreeBSD Project's webpage, whereas, a query for ftp.freebsd.org will return the IP of the corresponding ftp machine. Likewise, the opposite can happen. A query for an IP address can resolve its hostname. DNS DNS is coordinated across the Internet through a somewhat complex system of authoritative root name servers, and other smaller-scale nameservers who host and relay individual domain information. This document refers to BIND 8.x, as it is the most current, stable version used in FreeBSD. RFC1034 and RFC1035 dictates the DNS protocol. Currently, BIND is maintained by the Internet Software Consortium (www.isc.org) Terminology zones zone - Each individual domain, subdomain, or 'area' dictated by DNS is considered a zone. Examples of zones: . is the root zone org. is a zone under the root zone foobardomain.org is a zone under the org. zone foo.foobardomain.org. is a subdomain, a zone under the foobardomain.org. zone 1.2.3.in-addr.arpa is a zone referencing all ips which fall under the 3.2.1.* ip space. named, bind, name server - these are all common names for the BIND name server package within FreeBSD. resolver resolver - a network process by which a system queries a nameserver for answers root zone root zone - literally, a '.', refers to the root, or beginning zone. All zones fall under this, as do all files in fall under the root directory. It is the beginning of the Internet zone hierarchy origin - refers to the point of start for the particular zone forward dns - mapping of hostnames to ip addresses reverse DNS reverse dns - the opposite, mapping of ip addresses to hostnames Reasons to run a name server You need your machine to host DNS information to the world An authoritative nameserver replies exclusively to requests. For example, you register foobardomain.org and wish to assign hostnames to the proper IP addresses. A slave nameserver, which replies to queries for a domain when the primary is down or inaccessible. The above two can also be done with in-addr.arpa, IP to hostname entries You wish your machine to act as a local relay of DNS information DNS traffic has been measured to be about 5% or more of the total Internet traffic. A local DNS server may have some added benefit by providing a local cache of DNS information. For example, when one queries for www.freebsd.org, their resolver goes out to (usually) your ISP's name server, and retrieves the query. With a local, caching DNS server, the query only has to be made once to the outside world. Every additional query will not have to go outside of the local network, since the information is cached. How it works A DNS server in FreeBSD relies on the BIND daemon. This daemon is called 'named' for obvious reasons. named - the bind daemon ndc - name daemon control program /etc/namedb - directory where all the bind information resides /etc/namedb/named.conf - daemon configuration file zone files are usually contained within the /etc/namedb directory, and contain the information (query answers from your site) served by your name server. Starting BIND - BINDstarting + + BIND + starting + Since bind is installed by default, configuring it all is relatively simple. To ensure the named daemon is started at boot, put the following modifications in your /etc/rc.conf named_enable="YES" To start the daemon manually (after configuring it) &prompt.root; ndc start Configuration files - BINDconfiguration files + + BIND + configuration files + make-localhost Be sure to &prompt.root; cd /etc/namedb &prompt.root; sh make-localhost to properly create your local reverse dns zone file in /etc/namedb/localhost.rev. <filename>/etc/namedb/named.conf</filename> - // $FreeBSD: doc/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.sgml,v 1.48 2001/06/24 03:22:48 murray Exp $ + // $FreeBSD: doc/en_US.ISO8859-1/books/handbook/advanced-networking/chapter.sgml,v 1.49 2001/06/26 00:09:52 murray Exp $ // // Refer to the named(8) man page for details. If you are ever going // to setup a primary server, make sure you've understood the hairy // details of how DNS is working. Even with simple mistakes, you can // break connectivity for affected parties, or cause huge amount of // useless Internet traffic. options { directory "/etc/namedb"; // In addition to the "forwarders" clause, you can force your name // server to never initiate queries of its own, but always ask its // forwarders only, by enabling the following line: // // forward only; // If you've got a DNS server around at your upstream provider, enter // its IP address here, and enable the line below. This will make you // benefit from its cache, thus reduce overall DNS traffic in the Internet. /* forwarders { 127.0.0.1; }; */ Just as the comment says, if you want to benefit from your uplink's cache, you can enable this section of the config file. Normally, your nameserver will recursively query different nameservers until it finds the answer it is looking for. Having this enabled will have it automatically see if your uplink's (or whatever provided) ns has the requested query. If your uplink has a heavily trafficked, fast nameserver, enabling this properly could work to your advantage. 127.0.0.1 will *NOT* work here; change this to the IP of a nameserver at your uplink. /* * If there is a firewall between you and nameservers you want * to talk to, you might need to uncomment the query-source * directive below. Previous versions of BIND always asked * questions using port 53, but BIND 8.1 uses an unprivileged * port by default. */ // query-source address * port 53; /* * If running in a sandbox, you may have to specify a different * location for the dumpfile. */ // dump-file "s/named_dump.db"; }; // Note: the following will be supported in a future release. /* host { any; } { topology { 127.0.0.0/8; }; }; */ // Setting up secondaries is way easier and the rough picture for this // is explained below. // // If you enable a local name server, don't forget to enter 127.0.0.1 // into your /etc/resolv.conf so this server will be queried first. // Also, make sure to enable it in /etc/rc.conf. zone "." { type hint; file "named.root"; }; zone "0.0.127.IN-ADDR.ARPA" { type master; file "localhost.rev"; }; zone "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.IP6.INT" { type master; file "localhost.rev"; }; // NB: Do not use the IP addresses below, they are faked, and only // serve demonstration/documentation purposes! // // Example secondary config entries. It can be convenient to become // a secondary at least for the zone where your own domain is in. Ask // your network administrator for the IP address of the responsible // primary. // // Never forget to include the reverse lookup (IN-ADDR.ARPA) zone! // (This is the first bytes of the respective IP address, in reverse // order, with ".IN-ADDR.ARPA" appended.) // // Before starting to setup a primary zone, better make sure you fully // understand how DNS and BIND works, however. There are sometimes // unobvious pitfalls. Setting up a secondary is comparably simpler. // // NB: Don't blindly enable the examples below. :-) Use actual names // and addresses instead. // // NOTE!!! FreeBSD runs bind in a sandbox (see named_flags in rc.conf). // The directory containing the secondary zones must be write accessible // to bind. The following sequence is suggested: // // mkdir /etc/namedb/s // chown bind:bind /etc/namedb/s // chmod 750 /etc/namedb/s /* zone "domain.com" { type slave; file "s/domain.com.bak"; masters { 192.168.1.1; }; }; zone "0.168.192.in-addr.arpa" { type slave; file "s/0.168.192.in-addr.arpa.bak"; masters { 192.168.1.1; }; }; */ These are example slave entries, read below to see more. For each new domain added to your nameserver, you must add one of these entries to your named.conf The simplest zone entry, can look like zone "foobardomain.org" { type master; file "foorbardomain.org"; }; For a master entry with the zone information within foobardomain.org, or zone "foobardomain.org" { type slave; file "foobardomain.org"; }; for a slave. Note that slave zones automatically query the listed master (authoritative) name servers for the zone file. Zone files An example master 'foobardomain.org' (existing within /etc/namedb/foobardomain.org) is as follows: $TTL 3600 foobardomain.org. IN SOA ns1.foobardomain.org. admin.foobardomain.org. ( 5 ; Serial 10800 ; Refresh 3600 ; Retry 604800 ; Expire 86400 ) ; Minimum TTL ; DNS Servers @ IN NS ns1.foobardomain.org. @ IN NS ns2.foobardomain.org. ; Machine Names localhost IN A 127.0.0.1 ns1 IN A 3.2.1.2 ns2 IN A 3.2.1.3 mail IN A 3.2.1.10 @ IN A 3.2.1.30 ; Aliases www IN CNAME @ ; MX Record @ IN MX 10 mail.foobardomain.org. Note that every hostname ending in a '.' is an exact hostname, whereas everything without a trailing '.' is referenced to the origin. For example, www is translated into www + origin. In our fictitious zone file, our origin is foobardomain.org, so www would be www.foobardomain.org. The format of this file follows: recordname IN recordtype value - DNSrecords + + DNS + records + The most commonly used DNS records: SOA - start of zone authority NS - an authoritative nameserver A - A host address CNAME - the canonical name for an alias MX - mail exchange PTR - a domain name pointer (used in reverse dns) foobardomain.org. IN SOA ns1.foobardomain.org. admin.foobardomain.org. ( 5 ; Serial 10800 ; Refresh after 3 hours 3600 ; Retry after 1 hour 604800 ; Expire after 1 week 86400 ) ; Minimum TTL of 1 day foobardomain.org. - the domain name, also the origin for this zone file. ns1.foobardomain.org. - the primary/authoritative nameserver for this zone admin.foobardomain.org. - the responsible person for this zone, e-mail address with @ replaced. (admin@foobardomain.org becomes admin.foobardomain.org) 5 - the serial number of the file. this must be incremented each time the zone file is modified. Nowadays, many admins prefer a yyyymmddrr format for the serial number. 2001041002 would mean last modified 04/10/2001, the latter 02 being the second time the zone file has been modified this day. The serial number is important as it alerts slave nameservers for a zone when it is updated. @ IN NS ns1.foobardomain.org. This is an NS entry. Every nameserver that is going to reply authoritatively for the zone must have one of these entries. The @ as seen here could have been 'foobardomain.org.' The @ translates to the origin. localhost IN A 127.0.0.1 ns1 IN A 3.2.1.2 ns2 IN A 3.2.1.3 mail IN A 3.2.1.10 @ IN A 3.2.1.30 The A record indicates machine names. As seen above, ns1.foobardomain.org would resolve to 3.2.1.2. Again, the origin symbol, @, is used here, thus meaning foobardomain.org would resolve to 3.2.1.30. www IN CNAME @ The canonical name record is usually used for giving aliases to a machine. In the example, www is aliased to the machine addressed to the origin, or foobardomain.org (3.2.1.30). CNAMEs can be used to provide alias hostnames, or round robin one hostname among multiple machines. @ IN MX 10 mail.foobardomain.org. The MX record indicates which mail servers are responsible for handling incoming mail for the zone. mail.foobardomain.org is the hostname of the mail server, and 10 being the priority of that mailserver. One can have several mailservers, with priorities of 3, 2, 1. A mail server attempting to deliver to foobardomain.org would first try the highest priority MX, then the second highest, etc, until the mail can be properly delivered. For in-addr.arpa zone files (reverse dns), the same format is used, except with PTR entries instead of A or CNAME. $TTL 3600 1.2.3.in-addr.arpa. IN SOA ns1.foobardomain.org. admin.foobardomain.org. ( 5 ; Serial 10800 ; Refresh 3600 ; Retry 604800 ; Expire 3600 ) ; Minimum @ IN NS ns1.foobardomain.org. @ IN NS ns2.foobardomain.org. 2 IN PTR ns1.foobardomain.org. 3 IN PTR ns2.foobardomain.org. 10 IN PTR mail.foobardomain.org. 30 IN PTR foobardomain.org. This file gives the proper IP to hostname mappings of our above fictitious domain. Caching Name Server - BINDcaching name server + + BIND + caching name server + A caching nameserver is simply a nameserver that is not authoritative for any zones. It simply asks queries of its own, and remembers them for later use. To set one up, just configure the name server as usual, omitting any inclusions of zones. Running named in a Sandbox - BINDrunning in a sandbox + + BIND + running in a sandbox + Contributed by Mike Makonnen mike_makonnen@yahoo.com, May 1, 2001 chroot For added security you may want to run &man.named.8; in a sandbox. This will reduce the potential damage should it be compromised. If you include a sandbox directory in its command line, named will &man.chroot.8; into that directory immediately upon finishing processing its command line. It is also a good idea to have named run as a non-privileged user in the sandbox. The default FreeBSD install contains a user bind with group bind. If we wanted the sandbox in the /etc/namedb/sandbox directory the command line for named would look like this: &prompt.root; /usr/sbin/named -u bind -g bind -t /etc/namedb/sandbox <path_to_named.conf> The following steps should be taken in order to successfully run named in a sandbox. Throughout the following discussion we will assume the path to your sandbox is /etc/namedb/sandbox Create the sandbox directory: /etc/namedb/sandbox Create other necessary directories off of the sandbox directory: etc and var/run copy /etc/localtime to sandbox/etc make bind:bind the owner of all files and directories in the sandbox: &prompt.root; chown -R bind:bind /etc/namedb/sandbox &prompt.root; chmod -R 750 /etc/namedb/sandbox There are some issues you need to be aware of when running named in a sandbox. Your &man.named.conf.5; file and all your zone files must be in the sandbox sandbox/etc/localtime is needed in order to have the correct time for your time zone in log messages. &man.named.8; will write its process id to a file in sandbox/var/run The Unix socket used for communication by the &man.ndc.8; utility will be created in sandbox/var/run When using the ndc utility you need to specify the location of the Unix socket created in the sandbox, by &man.named.8;, by using the -c switch: &prompt.root; ndc -c /etc/namedb/sandbox/var/run/ndc If you enable logging to file, the log files must be in the sandbox &man.named.8; can be started in a sandbox properly, if the following is in /etc/rc.conf named_flags="-u bind -g bind -t /etc/namedb/sandbox" How to use the nameserver If setup properly, the nameserver should be accessible through the network and locally. /etc/resolv.conf must contain a nameserver entry with the local ip so it will query the local name server first. To access it over the network, the machine must have the nameserver's IP address set properly in its own nameserver configuration options. Security Although BIND is the most common implementation of DNS, there is always the issue of security. Possible and exploitable security holes are sometimes found. It is a good idea to subscribe to CERT and freebsd-announce to stay up to date with the current Internet and FreeBSD security issues. If a problem arises, keeping your sources up to date and having a fresh build of named can't hurt. Further Reading &man.ndc.8; &man.named.8; &man.named.conf.5; Official ISC BIND Page http://www.isc.org/products/BIND/ BIND FAQ http://www.nominum.com/resources/faqs/bind-faqs.html O'Reilly DNS and BIND 4th Edition RFC1034 - Domain Names - Concepts and Facilities RFC1035 - Domain Names - Implementation and Specification Network Address Translation daemon (natd) Contributed by &a.chern;, June 2001. Overview natd FreeBSD's Network Address Translation daemon, commonly known as &man.natd.8; is a daemon that accepts incoming raw IP packets, changes the source to the local machine and re-injects these packets back into the outgoing IP packet stream. natd does this by changing the source ip and port such that when data is received back, it is able to determine the original location of the data and forward it back to its original requestor. Internet connection sharing IP masquerading The most common use of NAT is to perform what is commonly known as Internet Connection Sharing. Setup Due to the diminishing ip space in ipv4, and the increased number of users on high-speed consumer lines such as cable or DSL, people are in more and more need of an Internet Connection Sharing solution. The ability to connect several computers online through one connection and ip makes &man.natd.8; a reasonable choice. Most commonly, a user has a machine connected to a cable or DSL line with one ip and wishes to use this one connected computer to provide internet access to several more over a LAN. To do this, the FreeBSD machine on the Internet must act as a gateway. This gateway machine must have two NICs--one for connecting to the Internet router, the other connecting to a LAN. All the machines on the LAN are connected through a hub or switch. _______ __________ ________ | | | | | | | Hub |-----| Client B |-----| Router |----- Internet |_______| |__________| |________| | ____|_____ | | | Client A | |__________| Network Layout With this setup, the machine without Internet access can use the machine with access as a gateway to access the outside world. - kernelconfiguration + + kernel + configuration + Configuration The following options must be in the kernel configuration file: options IPFIREWALL options IPDIVERT Additionally, at choice, the following may also be suitable: options IPFIREWALL_DEFAULT_TO_ACCEPT options IPFIREWALL_VERBOSE The following must be in /etc/rc.conf: gateway_enable="YES" firewall_enable="YES" firewall_type="OPEN" natd_enable="YES" natd_interface="fxp0" natd_flags="" gateway_enable="YES" Sets up the machine to act as a gateway. Running sysctl -w net.inet.ip.forwarding=1 would have the same effect. firewall_enable="YES" Enables the firewall rules in /etc/rc.firewall at boot. firewall_type="OPEN" This specifies a predefined firewall ruleset that allows anything in. See /etc/rc.firewall for additional types. natd_interface="fxp0" Indicates which interface to forward packets through. (the interface connected to the Internet) natd_flags="" Any additional configuration options passed to &man.natd.8; on boot. Having the previous options defined in /etc/rc.conf would run natd -interface fxp0 at boot. This can also be run manually. Each machine and interface behind the LAN should be assigned ip numbers in the private network space as defined by RFC 1918 and have a default gateway of the natd machine's internal ip. For example, client a and b behind the LAN have ips of 192.168.0.2 and 192.168.0.3, while the natd machine's LAN interface has an ip of 192.168.0.1. Client a and b's default gateway must be set to that of the natd machine, 192.168.0.1. The natd machine's external, or Internet interface does not require any special modification for natd to work. Port Redirection The drawback with natd is that the LAN clients are not accessible from the Internet. Clients on the LAN can make outgoing connections to the world but cannot receive incoming ones. This presents a problem if trying to run Internet services on one of the LAN client machines. A simple way around this is to redirect selected Internet ports on the natd machine to a LAN client. For example, an IRC server runs on Client A, and a web server runs on Client B. For this to work properly, connections received on ports 6667 (irc) and 80 (web) must be redirected to the respective machines. The -redirect_port must be passed to &man.natd.8; with the proper options. The syntax is as follows: -redirect_port proto targetIP:targetPORT[-targetPORT] [aliasIP:]aliasPORT[-aliasPORT] [remoteIP[:remotePORT[-remotePORT]]] In the above example, the argument should be: -redirect_port tcp 192.168.0.2:6667 6667 -redirect_port tcp 192.168.0.3:80 80 This will redirect the proper tcp ports to the LAN client machines. The -redirect_port argument can be used to indicate port ranges over individual ports. For example, tcp 192.168.0.2:2000-3000 2000-3000 would redirect all connections received on ports 2000 to 3000 to ports 2000 to 3000 on Client A. These options can be used when directly running &man.natd.8; or placed within the natd_flags="" option in /etc/rc.conf. For further configuration options, consult &man.natd.8; Address Redirection address redirection Address redirection is useful if several ips are available, yet they must be on one machine. With this, &man.natd.8; can assign each LAN client its own external ip. &man.natd.8; then rewrites outgoing packets from the LAN clients with the proper external ip and redirects all traffic incoming on that particular ip back to the specific LAN client. This is also known as static NAT. For example, the ips 128.1.1.1, 128.1.1.2, and 128.1.1.3 belong to the natd gateway machine. 128.1.1.1 can be used as the natd gateway machine's external ip address, while 128.1.1.2 and 128.1.1.3 are forwarded back to LAN clients A and B. The -redirect_address syntax is as follows: -redirect_address localIP publicIP localIP The internal ip of the LAN client. publicIP The external ip corresponding to the LAN client. In the example, this argument would read: -redirect_address 192.168.0.2 128.1.1.2 -redirect_address 192.168.0.3 128.1.1.3 Like -redirect_port, these arguments are also placed within natd_flags of /etc/rc.conf. With address redirection, there is no need for port redirection since all data received on a particular ip address is redirected. The external ips on the natd machine must be active and aliased to the external interface. Look at &man.rc.conf.5; to do so. diff --git a/en_US.ISO8859-1/books/handbook/backups/chapter.sgml b/en_US.ISO8859-1/books/handbook/backups/chapter.sgml index 29588db867..64ca668398 100644 --- a/en_US.ISO8859-1/books/handbook/backups/chapter.sgml +++ b/en_US.ISO8859-1/books/handbook/backups/chapter.sgml @@ -1,778 +1,810 @@ Backups Synopsis The following chapter will cover methods of backing up data, and the programs used to create those backups. If you would like to contribute something to this section, send it to the &a.doc;. Tape Media tape media The major tape media are the 4mm, 8mm, QIC, mini-cartridge and DLT. 4mm (DDS: Digital Data Storage) - tape mediaDDS (4mm) tapes - tape mediaQIC tapes + + tape media + DDS (4mm) tapes + + + tape media + QIC tapes + 4mm tapes are replacing QIC as the workstation backup media of choice. This trend accelerated greatly when Conner purchased Archive, a leading manufacturer of QIC drives, and then stopped production of QIC drives. 4mm drives are small and quiet but do not have the reputation for reliability that is enjoyed by 8mm drives. The cartridges are less expensive and smaller (3 x 2 x 0.5 inches, 76 x 51 x 12 mm) than 8mm cartridges. 4mm, like 8mm, has comparatively short head life for the same reason, both use helical scan. Data throughput on these drives starts ~150kB/s, peaking at ~500kB/s. Data capacity starts at 1.3 GB and ends at 2.0 GB. Hardware compression, available with most of these drives, approximately doubles the capacity. Multi-drive tape library units can have 6 drives in a single cabinet with automatic tape changing. Library capacities reach 240 GB. The DDS-3 standard now supports tape capacities up to 12GB (or 24GB compressed). 4mm drives, like 8mm drives, use helical-scan. All the benefits and drawbacks of helical-scan apply to both 4mm and 8mm drives. Tapes should be retired from use after 2,000 passes or 100 full backups. 8mm (Exabyte) - tape mediaExabyte (8mm) - tapes + + tape media + Exabyte (8mm) tapes + 8mm tapes are the most common SCSI tape drives; they are the best choice of exchanging tapes. Nearly every site has an exabyte 2 GB 8mm tape drive. 8mm drives are reliable, convenient and quiet. Cartridges are inexpensive and small (4.8 x 3.3 x 0.6 inches; 122 x 84 x 15 mm). One downside of 8mm tape is relatively short head and tape life due to the high rate of relative motion of the tape across the heads. Data throughput ranges from ~250kB/s to ~500kB/s. Data sizes start at 300 MB and go up to 7 GB. Hardware compression, available with most of these drives, approximately doubles the capacity. These drives are available as single units or multi-drive tape libraries with 6 drives and 120 tapes in a single cabinet. Tapes are changed automatically by the unit. Library capacities reach 840+ GB. The Exabyte Mammoth model supports 12GB on one tape (24GB with compression) and costs approximately twice as much as conventional tape drives. Data is recorded onto the tape using helical-scan, the heads are positioned at an angle to the media (approximately 6 degrees). The tape wraps around 270 degrees of the spool that holds the heads. The spool spins while the tape slides over the spool. The result is a high density of data and closely packed tracks that angle across the tape from one edge to the other. QIC - tape mediaQIC-150 + + tape media + QIC-150 + QIC-150 tapes and drives are, perhaps, the most common tape drive and media around. QIC tape drives are the least expensive "serious" backup drives. The downside is the cost of media. QIC tapes are expensive compared to 8mm or 4mm tapes, up to 5 times the price per GB data storage. But, if your needs can be satisfied with a half-dozen tapes, QIC may be the correct choice. QIC is the most common tape drive. Every site has a QIC drive of some density or another. Therein lies the rub, QIC has a large number of densities on physically similar (sometimes identical) tapes. QIC drives are not quiet. These drives audibly seek before they begin to record data and are clearly audible whenever reading, writing or seeking. QIC tapes measure (6 x 4 x 0.7 inches; 15.2 x 10.2 x 1.7 mm). Mini-cartridges, which also use 1/4" wide tape are discussed separately. Tape libraries and changers are not available. Data throughput ranges from ~150kB/s to ~500kB/s. Data capacity ranges from 40 MB to 15 GB. Hardware compression is available on many of the newer QIC drives. QIC drives are less frequently installed; they are being supplanted by DAT drives. Data is recorded onto the tape in tracks. The tracks run along the long axis of the tape media from one end to the other. The number of tracks, and therefore the width of a track, varies with the tape's capacity. Most if not all newer drives provide backward-compatibility at least for reading (but often also for writing). QIC has a good reputation regarding the safety of the data (the mechanics are simpler and more robust than for helical scan drives). Tapes should be retired from use after 5,000 backups. * Mini-Cartridge ]]> DLT - tape mediaDLT + + tape media + DLT + DLT has the fastest data transfer rate of all the drive types listed here. The 1/2" (12.5mm) tape is contained in a single spool cartridge (4 x 4 x 1 inches; 100 x 100 x 25 mm). The cartridge has a swinging gate along one entire side of the cartridge. The drive mechanism opens this gate to extract the tape leader. The tape leader has an oval hole in it which the drive uses to "hook" the tape. The take-up spool is located inside the tape drive. All the other tape cartridges listed here (9 track tapes are the only exception) have both the supply and take-up spools located inside the tape cartridge itself. Data throughput is approximately 1.5MB/s, three times the throughput of 4mm, 8mm, or QIC tape drives. Data capacities range from 10GB to 20GB for a single drive. Drives are available in both multi-tape changers and multi-tape, multi-drive tape libraries containing from 5 to 900 tapes over 1 to 20 drives, providing from 50GB to 9TB of storage. With compression, DLT Type IV format supports up to 70GB capacity. Data is recorded onto the tape in tracks parallel to the direction of travel (just like QIC tapes). Two tracks are written at once. Read/write head lifetimes are relatively long; once the tape stops moving, there is no relative motion between the heads and the tape. AIT - tape mediaAIT + + tape media + AIT + AIT is a new format from Sony, and can hold up to 50GB (with compression) per tape. The tapes contain memory chips which retain an index of the tape's contents. This index can be rapidly read by the tape drive to determine the position of files on the tape, instead of the several minutes that would be required for other tapes. Software such as SAMS:Alexandria can operate forty or more AIT tape libraries, communicating directly with the tape's memory chip to display the contents on screen, determine what files where backed up to which tape, locate the correct tape, load it, and restore the data from the tape. Libraries like this cost in the region of $20,000, pricing them a little out of the hobbyist market. Using a New Tape for the First Time The first time that you try to read or write a new, completely blank tape, the operation will fail. The console messages should be similar to: sa0(ncr1:4:0): NOT READY asc:4,1 sa0(ncr1:4:0): Logical unit is in process of becoming ready The tape does not contain an Identifier Block (block number 0). All QIC tape drives since the adoption of QIC-525 standard write an Identifier Block to the tape. There are two solutions: mt fsf 1 causes the tape drive to write an Identifier Block to the tape. Use the front panel button to eject the tape. Re-insert the tape and &man.dump.8; data to the tape. &man.dump.8; will report DUMP: End of tape detected and the console will show: HARDWARE FAILURE info:280 asc:80,96 rewind the tape using: mt rewind Subsequent tape operations are successful. Backup Programs backup software The three major programs are &man.dump.8;, &man.tar.1;, and &man.cpio.1;. Dump and Restore - backup softwaredump / restore + + backup software + dump / restore + dump restore &man.dump.8; and &man.restore.8; are the traditional Unix backup programs. They operate on the drive as a collection of disk blocks, below the abstractions of files, links and directories that are created by the filesystems. &man.dump.8; backs up devices, entire filesystems, not parts of a filesystem and not directory trees that span more than one filesystem, using either soft links &man.ln.1; or mounting one filesystem onto another. &man.dump.8; does not write files and directories to tape, but rather writes the data blocks that are the building blocks of files and directories. &man.dump.8; has quirks that remain from its early days in Version 6 of ATT Unix (circa 1975). The default parameters are suitable for 9-track tapes (6250 bpi), not the high-density media available today (up to 62,182 ftpi). These defaults must be overridden on the command line to utilize the capacity of current tape drives. rhosts &man.rdump.8; and &man.rrestore.8; backup data across the network to a tape drive attached to another computer. Both programs rely upon &man.rcmd.3; and &man.ruserok.3; to access the remote tape drive. Therefore, the user performing the backup must have rhosts access to the remote computer. The arguments to &man.rdump.8; and &man.rrestore.8; must suitable to use on the remote computer. (e.g. When rdumping from a FreeBSD computer to an Exabyte tape drive connected to a Sun called komodo, use: /sbin/rdump 0dsbfu 54000 13000 126 komodo:/dev/nrsa8 /dev/rda0a 2>&1) Beware: there are security implications to allowing rhosts commands. Evaluate your situation carefully. Tar - backup softwaretar + + backup software + tar + &man.tar.1; also dates back to Version 6 of ATT Unix (circa 1975). &man.tar.1; operates in cooperation with the filesystem; &man.tar.1; writes files and directories to tape. &man.tar.1; does not support the full range of options that are available from &man.cpio.1;, but &man.tar.1; does not require the unusual command pipeline that &man.cpio.1; uses. tar Most versions of &man.tar.1; do not support backups across the network. The GNU version of &man.tar.1;, which FreeBSD utilizes, supports remote devices using the same syntax as &man.rdump.8;. To &man.tar.1; to an Exabyte tape drive connected to a Sun called komodo, use: /usr/bin/tar cf komodo:/dev/nrsa8 . 2>&1. For versions without remote device support, you can use a pipeline and &man.rsh.1; to send the data to a remote tape drive. &prompt.root; tar cf - . | rsh hostname dd of=tape-device obs=20b If you're worried about the security of backing over a network you should use the &man.ssh.1; command instead of &man.rsh.1;. Cpio - backup softwarecpio + + backup software + cpio + &man.cpio.1; is the original Unix file interchange tape program for magnetic media. &man.cpio.1; has options (among many others) to perform byte-swapping, write a number of different archives format, and pipe the data to other programs. This last feature makes &man.cpio.1; and excellent choice for installation media. &man.cpio.1; does not know how to walk the directory tree and a list of files must be provided through stdin. cpio &man.cpio.1; does not support backups across the network. You can use a pipeline and &man.rsh.1; to send the data to a remote tape drive. &prompt.root; for f in directory_list; do find $f >> backup.list done &prompt.root; cpio -v -o --format=newc < backup.list | ssh user@host "cat > backup_device Where directory_list is the list of directories you want to back up, user@host is the user/hostname combination that will be performing the backups, and backup_device is where the backups should be written to (e.g., /dev/nrsa0). Pax - backup softwarepax + + backup software + pax + pax POSIX IEEE &man.pax.1; is IEEE/POSIX's answer to &man.tar.1; and &man.cpio.1;. Over the years the various versions of &man.tar.1; and &man.cpio.1; have gotten slightly incompatible. So rather than fight it out to fully standardize them, POSIX created a new archive utility. &man.pax.1; attempts to read and write many of the various &man.cpio.1; and &man.tar.1; formats, plus new formats of its own. Its command set more resembles &man.cpio.1; than &man.tar.1;. Amanda - backup softwareamanda + + backup software + amanda + amanda Amanda (Advanced Maryland Network Disk Archiver) is a client/server backup system, rather than a single program. An Amanda server will backup to a single tape drive any number of computers that have Amanda clients and network communications with the Amanda server. A common problem at locations with a number of large disks is the length of time required to backup to data directly to tape exceeds the amount of time available for the task. Amanda solves this problem. Amanda can use a "holding disk" to backup several filesystems at the same time. Amanda creates "archive sets": a group of tapes used over a period of time to create full backups of all the filesystems listed in Amanda's configuration file. The "archive set" also contains nightly incremental (or differential) backups of all the filesystems. Restoring a damaged filesystem requires the most recent full backup and the incremental backups. The configuration file provides fine control backups and the network traffic that Amanda generates. Amanda will use any of the above backup programs to write the data to tape. Amanda is available as either a port or a package, it is not installed by default. Do Nothing Do nothing is not a computer program, but it is the most widely used backup strategy. There are no initial costs. There is no backup schedule to follow. Just say no. If something happens to your data, grin and bear it! If your time and your data is worth little to nothing, then Do nothing is the most suitable backup program for your computer. But beware, Unix is a useful tool, you may find that within six months you have a collection of files that are valuable to you. Do nothing is the correct backup method for /usr/obj and other directory trees that can be exactly recreated by your computer. An example is the files that comprise these handbook pages-they have been generated from SGML input files. Creating backups of these HTML files is not necessary. The SGML source files are backed up regularly. Which Backup Program is Best? LISA &man.dump.8; Period. Elizabeth D. Zwicky torture tested all the backup programs discussed here. The clear choice for preserving all your data and all the peculiarities of Unix filesystems is &man.dump.8;. Elizabeth created filesystems containing a large variety of unusual conditions (and some not so unusual ones) and tested each program by doing a backup and restore of that filesystems. The peculiarities included: files with holes, files with holes and a block of nulls, files with funny characters in their names, unreadable and unwritable files, devices, files that change size during the backup, files that are created/deleted during the backup and more. She presented the results at LISA V in Oct. 1991. See torture-testing Backup and Archive Programs. Emergency Restore Procedure Before the Disaster There are only four steps that you need to perform in preparation for any disaster that may occur. disklabel First, print the disklabel from each of your disks (e.g. disklabel da0 | lpr), your filesystem table (/etc/fstab) and all boot messages, two copies of each. fix-it floppies Second, determine that the boot and fix-it floppies (boot.flp and fixit.flp) have all your devices. The easiest way to check is to reboot your machine with the boot floppy in the floppy drive and check the boot messages. If all your devices are listed and functional, skip on to step three. Otherwise, you have to create two custom bootable floppies which has a kernel that can mount your all of your disks and access your tape drive. These floppies must contain: &man.fdisk.8;, &man.disklabel.8;, &man.newfs.8;, &man.mount.8;, and whichever backup program you use. These programs must be statically linked. If you use &man.dump.8;, the floppy must contain &man.restore.8;. Third, create backup tapes regularly. Any changes that you make after your last backup may be irretrievably lost. Write-protect the backup tapes. Fourth, test the floppies (either boot.flp and fixit.flp or the two custom bootable floppies you made in step two.) and backup tapes. Make notes of the procedure. Store these notes with the bootable floppy, the printouts and the backup tapes. You will be so distraught when restoring that the notes may prevent you from destroying your backup tapes (How? In place of tar xvf /dev/rsa0, you might accidently type tar cvf /dev/rsa0 and over-write your backup tape). For an added measure of security, make bootable floppies and two backup tapes each time. Store one of each at a remote location. A remote location is NOT the basement of the same office building. A number of firms in the World Trade Center learned this lesson the hard way. A remote location should be physically separated from your computers and disk drives by a significant distance. An example script for creating a bootable floppy: /mnt/sbin/init gzip -c -best /sbin/fsck > /mnt/sbin/fsck gzip -c -best /sbin/mount > /mnt/sbin/mount gzip -c -best /sbin/halt > /mnt/sbin/halt gzip -c -best /sbin/restore > /mnt/sbin/restore gzip -c -best /bin/sh > /mnt/bin/sh gzip -c -best /bin/sync > /mnt/bin/sync cp /root/.profile /mnt/root cp -f /dev/MAKEDEV /mnt/dev chmod 755 /mnt/dev/MAKEDEV chmod 500 /mnt/sbin/init chmod 555 /mnt/sbin/fsck /mnt/sbin/mount /mnt/sbin/halt chmod 555 /mnt/bin/sh /mnt/bin/sync chmod 6555 /mnt/sbin/restore # # create the devices nodes # cd /mnt/dev ./MAKEDEV std ./MAKEDEV da0 ./MAKEDEV da1 ./MAKEDEV da2 ./MAKEDEV sa0 ./MAKEDEV pty0 cd / # # create minimum filesystem table # cat > /mnt/etc/fstab < /mnt/etc/passwd < /mnt/etc/master.passwd < After the Disaster The key question is: did your hardware survive? You have been doing regular backups so there is no need to worry about the software. If the hardware has been damaged. First, replace those parts that have been damaged. If your hardware is okay, check your floppies. If you are using a custom boot floppy, boot single-user (type -s at the boot: prompt). Skip the following paragraph. If you are using the boot.flp and fixit.flp floppies, keep reading. Insert the boot.flp floppy in the first floppy drive and boot the computer. The original install menu will be displayed on the screen. Select the Fixit--Repair mode with CDROM or floppy. option. Insert the fixit.flp when prompted. restore and the other programs that you need are located in /mnt2/stand. Recover each filesystem separately. mount root partition disklabel newfs Try to &man.mount.8; (e.g. mount /dev/da0a /mnt) the root partition of your first disk. If the disklabel was damaged, use &man.disklabel.8; to re-partition and label the disk to match the label that your printed and saved. Use &man.newfs.8; to re-create the filesystems. Re-mount the root partition of the floppy read-write (mount -u -o rw /mnt). Use your backup program and backup tapes to recover the data for this filesystem (e.g. restore vrf /dev/sa0). Unmount the filesystem (e.g. umount /mnt) Repeat for each filesystem that was damaged. Once your system is running, backup your data onto new tapes. Whatever caused the crash or data loss may strike again. An another hour spent now, may save you from further distress later. * I did not prepare for the Disaster, What Now? ]]> What about Backups to Floppies? Can I use floppies for backing up my data? backup floppies floppy disks Floppy disks are not really a suitable media for making backups as: The media is unreliable, especially over long periods of time Backing up and restoring is very slow They have a very limited capacity (the days of backing up an entire hard disk onto a dozen or so floppies has long since passed). However, if you have no other method of backing up your data then floppy disks are better than no backup at all. If you do have to use floppy disks then ensure that you use good quality ones. Floppies that have been lying around the office for a couple of years are a bad choice. Ideally use new ones from a reputable manufacturer. So how do I backup my data to floppies? The best way to backup to floppy disk is to use &man.tar.1; with the (multi volume) option, which allows backups to span multiple floppies. To backup all the files in the current directory and sub-directory use this (as root): &prompt.root; tar Mcvf /dev/fd0 * When the first floppy is full &man.tar.1; will prompt you to insert the next volume (because &man.tar.1; is media independent it refers to volumes. In this context it means floppy disk) Prepare volume #2 for /dev/fd0 and hit return: This is repeated (with the volume number incrementing) until all the specified files have been archived. Can I compress my backups? tar gzip compression Unfortunately, &man.tar.1; will not allow the option to be used for multi-volume archives. You could, of course, &man.gzip.1; all the files, &man.tar.1; them to the floppies, then &man.gunzip.1; the files again! How do I restore my backups? To restore the entire archive use: &prompt.root; tar Mxvf /dev/fd0 To restore only specific files you can either start with the first floppy and use: &prompt.root; tar Mxvf /dev/fd0 filename &man.tar.1; will prompt you to insert subsequent floppies until it finds the required file. Alternatively, if you know which floppy the file is on then you can simply insert that floppy and use the same command as above. Note that if the first file on the floppy is a continuation from the previous one then &man.tar.1; will warn you that it cannot restore it, even if you have not asked it to! diff --git a/en_US.ISO8859-1/books/handbook/disks/chapter.sgml b/en_US.ISO8859-1/books/handbook/disks/chapter.sgml index fb196d3b0b..9d8d4adbd1 100644 --- a/en_US.ISO8859-1/books/handbook/disks/chapter.sgml +++ b/en_US.ISO8859-1/books/handbook/disks/chapter.sgml @@ -1,1131 +1,1133 @@ Disks Synopsis This chapter covers how to use disks, whether physical, memory, or networked, on FreeBSD. BIOS Drive Numbering Before you install and configure FreeBSD on your system, there is an important subject that you should be aware of if, especially if you have multiple hard drives. DOS Microsoft Windows In a PC running DOS or any of the BIOS-dependent operating systems (WINxxx), the BIOS is able to abstract the normal disk drive order, and the operating system goes along with the change. This allows the user to boot from a disk drive other than the so-called primary master. This is especially convenient for some users who have found that the simplest and cheapest way to keep a system backup is to buy an identical second hard drive, and perform routine copies of the first drive to the second drive using Ghost or XCOPY. Then, if the first drive fails, or is attacked by a virus, or is scribbled upon by an operating system defect, he can easily recover by instructing the BIOS to logically swap the drives. It's like switching the cables on the drives, but without having to open the case. SCSI BIOS More expensive systems with SCSI controllers often include BIOS extensions which allow the SCSI drives to be re-ordered in a similar fashion for up to seven drives. A user who is accustomed to taking advantage of these features may become surprised when the results with FreeBSD are not as expected. FreeBSD does not use the BIOS, and does not know the logical BIOS drive mapping. This can lead to very perplexing situations, especially when drives are physically identical in geometry, and have also been made as data clones of one another. When using FreeBSD, always restore the BIOS to natural drive numbering before installing FreeBSD, and then leave it that way. If you need to switch drives around, then do so, but do it the hard way, and open the case and move the jumpers and cables. An illustration from the files of Bill and Fred's Exceptional Adventures: Bill breaks-down an older Wintel box to make another FreeBSD box for Fred. Bill installs a single SCSI drive as SCSI unit zero, and installs FreeBSD on it. Fred begins using the system, but after several days notices that the older SCSI drive is reporting numerous soft errors, and reports this fact to Bill. After several more days, Bill decides it's time to address the situation, so he grabs an identical SCSI drive from the disk drive "archive" in the back room. An initial surface scan indicates that this drive is functioning well, so Bill installs this drive as SCSI unit four, and makes an image copy from drive zero to drive four. Now that the new drive is installed and functioning nicely, Bill decides that it's a good idea to start using it, so he uses features in the SCSI BIOS to re-order the disk drives so that the system boots from SCSI unit four. FreeBSD boots and runs just fine. Fred continues his work for several days, and soon Bill and Fred decide that it's time for a new adventure -- time to upgrade to a newer version of FreeBSD. Bill removes SCSI unit zero because it was a bit flaky, and replaces it with another identical disk drive from the "archive." Bill then installs the new version of FreeBSD onto the new SCSI unit zero using Fred's magic Internet FTP floppies. The installation goes well. Fred uses the new version of FreeBSD for a few days, and certifies that it is good enough for use in the engineering department...it's time to copy all of his work from the old version. So Fred mounts SCSI unit four (the latest copy of the older FreeBSD version). Fred is dismayed to find that none of his precious work is present on SCSI unit four. Where did the data go? When Bill made an image copy of the original SCSI unit zero onto SCSI unit four, unit four became the "new clone," When Bill re-ordered the SCSI BIOS so that he could boot from SCSI unit four, he was only fooling himself. FreeBSD was still running on SCSI unit zero. Making this kind of BIOS change will cause some or all of the Boot and Loader code to be fetched from the selected BIOS drive, but when the FreeBSD kernel drivers take-over, the BIOS drive numbering will be ignored, and FreeBSD will transition back to normal drive numbering. In the illustration at hand, the system continued to operate on the original SCSI unit zero, and all of Fred's data was there, not on SCSI unit four. The fact that the system appeared to be running on SCSI unit four was simply an artifact of human expectations. We are delighted to mention that no data bytes were killed or harmed in any way by our discovery of this phenomenon. The older SCSI unit zero was retrieved from the bone pile, and all of Fred's work was returned to him, (and now Bill knows that he can count as high as zero). Although SCSI drives were used in this illustration, the concepts apply equally to IDE drives. Disk Naming IDE SCSI RAID fash memory Physical drives come in two main flavors, IDE, or SCSI; but there are also drives backed by RAID controllers, flash memory, and so forth. Since these behave quite differently, they have their own drivers and devices. Physical Disk Naming Conventions Drive type Drive device name IDE hard drives ad in 4.0-RELEASE, wd before 4.0-RELEASE. IDE CDROM drives acd from 4.1-RELEASE, wcd before 4.0-RELEASE. SCSI hard drives da from 3.0-RELEASE, sd before 3.0-RELEASE. SCSI CDROM drives cd Assorted non-standard CDROM drives mcd for Mitsumi CD-ROM, scd for Sony CD-ROM, matcd for Matsushita/Panasonic CD-ROM Floppy drives fd SCSI tape drives sa from 3.0-RELEASE, st before 3.0-RELEASE. IDE tape drives ast from 4.0-RELEASE, wst before 4.0-RELEASE. Flash drives fla for DiskOnChip Flash device from 3.3-RELEASE. RAID drives myxd for Mylex, and amrd for AMI MegaRAID, idad for Compaq Smart RAID. from 4.0-RELEASE. id between 3.2-RELEASE and 4.0-RELEASE.
Slices and Partitions slices partitions dangerously dedicated Physical disks usually contain slices, unless they are dangerously dedicated. Slice numbers follow the device name, prefixed with an s: da0s1. Slices, dangerously dedicated physical drives, and other drives contain partitions, which represented as letters from a to h. b is reserved for swap partitions, and c is an unused partition the size of the entire slice or drive. This is explained in . Mounting and Unmounting Filesystems The filesystem is best visualized as a tree, rooted, as it were, at /. /dev, /usr, and the other directories in the root directory are branches, which may have their own branches, such as /usr/local, and so on. root filesystem There are various reasons to house some of these directories on separate filesystems. /var contains log, spool, and various types of temporary files, and as such, may get filled up. Filling up the root filesystem isn't a good idea, so splitting /var from / is often a good idea. Another common reason to contain certain directory trees on other filesystems is if they are to be housed on separate physical disks, or are separate virtual disks, such as Network File System mounts, or CDROM drives. The fstab File - filesystemsmounted with - fstab + + filesystems + mounted with fstab + During the boot process, filesystems listed in /etc/fstab are automatically mounted (unless they are listed with ). The /etc/fstab file contains a list of lines of the following format: device /mount-point fstype options dumpfreq passno device is a device name (which should exist), as explained in the Disk naming conventions above. mount-point is a directory (which should exist), on which to mount the filesystem. fstype is the filesystem type to pass to &man.mount.8;. The default FreeBSD filesystem is ufs. options is either for read-write filesystems, or for read-only filesystems, followed by any other options that may be needed. A common option is for filesystems not normally mounted during the boot sequence. Other options in the &man.mount.8; manual page. dumpfreq is the number of days the filesystem should be dumped, and passno is the pass number during which the filesystem is mounted during the boot sequence. The mount Command filesystemsmounting The &man.mount.8; command is what is ultimately used to mount filesystems. In its most basic form, you use: &prompt.root; mount device mountpoint There are plenty of options, as mentioned in the &man.mount.8; manual page, but the most common are: mount options Mount all filesystems in /etc/fstab, as modified by , if given. Do everything but actually mount the filesystem. Force the mounting the filesystem. Mount the filesystem read-only. fstype Mount the given filesystem as the given filesystem type, or mount only filesystems of the given type, if given the option. ufs is the default filesystem type. Update mount options on the filesystem. Be verbose. Mount the filesystem read-write. The takes a comma-separated list of the options, including the following: nodev Do not interpret special devices on the filesystem. Useful security option. noexec Do not allow execution of binaries on this filesystem. Useful security option. nosuid Do not interpret setuid or setgid flags on the filesystem. Useful security option. The umount Command filesystemsunmounting The umount command takes, as a parameter, one of a mountpoint, a device name, or the or option. All forms take to force unmounting, and for verbosity. and are used to unmount all mounted filesystems, possibly modified by the filesystem types listed after . , however, doesn't attempt to unmount the root filesystem. Adding Disks disksadding Originally contributed by &a.obrien; 26 April 1998 Lets say we want to add a new SCSI disk to a machine that currently only has a single drive. First turn off the computer and install the drive in the computer following the instructions of the computer, controller, and drive manufacturer. Due the wide variations of procedures to do this, the details are beyond the scope of this document. Login as user root. After you've installed the drive, inspect /var/run/dmesg.boot to ensure the new disk was found. Continuing with our example, the newly added drive will be da1 and we want to mount it on /1 (if you are adding an IDE drive, it will be wd1 in pre-4.0 systems, or ad1 in most 4.X systems). partitions slices fdisk Because FreeBSD runs on IBM-PC compatible computers, it must take into account the PC BIOS partitions. These are different from the traditional BSD partitions. A PC disk has up to four BIOS partition entries. If the disk is going to be truly dedicated to FreeBSD, you can use the dedicated mode. Otherwise, FreeBSD will have to live with in one of the PC BIOS partitions. FreeBSD calls the PC BIOS partitions slices so as not to confuse them with traditional BSD partitions. You may also use slices on a disk that is dedicated to FreeBSD, but used in a computer that also has another operating system installed. This is to not confuse the fdisk utility of the other operating system. In the slice case the drive will be added as /dev/da1s1e. This is read as: SCSI disk, unit number 1 (second SCSI disk), slice 1 (PC BIOS partition 1), and e BSD partition. In the dedicated case, the drive will be added simply as /dev/da1e. Using sysinstall sysinstalladding disks You may use /stand/sysinstall to partition and label a new disk using its easy to use menus. Either login as user root or use the su command. Run /stand/sysinstall and enter the Configure menu. With in the FreeBSD Configuration Menu, scroll down and select the Partition item. Next you should be presented with a list of hard drives installed in your system. If you do not see da1 listed, you need to recheck your physical installation and dmesg output in the file /var/run/dmesg.boot. Select da1 to enter the FDISK Partition Editor. Choose A to use the entire disk for FreeBSD. When asked if you want to remain cooperative with any future possible operating systems, answer YES. Write the changes to the disk using W. Now exit the FDISK editor using q. Next you will be asked about the Master Boot Record. Since you are adding a disk to an already running system, choose None. BSD partitions Next enter the Disk Label Editor. This is where you will create the traditional BSD partitions. A disk can have up to eight partitions, labeled a-h. A few of the partition labels have special uses. The a partition is used for the root partition (/). Thus only your system disk (e.g, the disk you boot from) should have an a partition. The b partition is used for swap partitions, and you may have many disks with swap partitions. The c partition addresses the entire disk in dedicated mode, or the entire FreeBSD slice in slice mode. The other partitions are for general use. Sysinstall's Label editor favors the e partition for non-root, non-swap partitions. With in the Label editor, create a single file system using C. When prompted if this will be a FS (file system) or swap, choose FS and give a mount point (e.g, /mnt). When adding a disk in post-install mode, Sysinstall will not create entries in /etc/fstab for you, so the mount point you specify isn't important. You are now ready to write the new label to the disk and create a file system on it. Do this by hitting W. Ignore any errors from Sysinstall that it could not mount the new partition. Exit the Label Editor and Sysinstall completely. The last step is to edit /etc/fstab to add an entry for your new disk. Using Command Line Utilities Using Slices This setup will allow your disk to work correctly with other operating systems that might be installed on your computer and will not confuse other operating systems' fdisk utilities. It is recommended to use this method for new disk installs. Only use dedicated mode if you have a good reason to do so! &prompt.root; dd if=/dev/zero of=/dev/rda1 bs=1k count=1 &prompt.root; fdisk -BI da1 #Initialize your new disk &prompt.root; disklabel -B -w -r da1s1 auto #Label it. &prompt.root; disklabel -e da1s1 # Now edit the disklabel you just created and add any partitions. &prompt.root; mkdir -p /1 &prompt.root; newfs /dev/da1s1e # Repeat this for every partition you created. &prompt.root; mount -t ufs /dev/da1s1e /1 # Mount the partition(s) &prompt.root; vi /etc/fstab # When satisfied, add the appropriate entry/entries to your /etc/fstab. If you have an IDE disk, substitute ad for da. On pre-4.x systems use wd. Dedicated OS/2 If you will not be sharing the new drive with another operating system, you may use the dedicated mode. Remember this mode can confuse Microsoft operating systems; however, no damage will be done by them. IBM's OS/2 however, will appropriate any partition it finds which it doesn't understand. &prompt.root; dd if=/dev/zero of=/dev/rda1 bs=1k count=1 &prompt.root; disklabel -Brw da1 auto &prompt.root; disklabel -e da1 # create the `e' partition &prompt.root; newfs -d0 /dev/rda1e &prompt.root; mkdir -p /1 &prompt.root; vi /etc/fstab # add an entry for /dev/da1e &prompt.root; mount /1 An alternate method is: &prompt.root; dd if=/dev/zero of=/dev/rda1 count=2 &prompt.root; disklabel /dev/rda1 | disklabel -BrR da1 /dev/stdin &prompt.root; newfs /dev/rda1e &prompt.root; mkdir -p /1 &prompt.root; vi /etc/fstab # add an entry for /dev/da1e &prompt.root; mount /1 Virtual Disks: Network, Memory, and File-Based Filesystems virtual disks disksvirtual Aside from the disks you physically insert into your computer: floppies, CDs, hard drives, and so forth; other forms of disks are understood by FreeBSD - the virtual disks. NFS Coda disksmemory These include network filesystems such as the Network Filesystem and Coda, memory-based filesystems such as md and file-backed filesystems created by vnconfig. vnconfig: file-backed filesystem disksfile-backed &man.vnconfig.8; configures and enables vnode pseudo disk devices. A vnode is a representation of a file, and is the focus of file activity. This means that &man.vnconfig.8; uses files to create and operate a filesystem. One possible use is the mounting of floppy or CD images kept in files. To mount an existing filesystem image: Using vnconfig to mount an existing filesystem image &prompt.root; vnconfig vn0 diskimage &prompt.root; mount /dev/vn0c /mnt To create a new filesystem image with vnconfig: Creating a New File-Backed Disk with vnconfig &prompt.root; dd if=/dev/zero of=newimage bs=1k count=5k 5120+0 records in 5120+0 records out &prompt.root; vnconfig -s labels -c vn0 newimage &prompt.root; disklabel -r -w vn0 auto &prompt.root; newfs vn0c Warning: 2048 sector(s) in last cylinder unallocated /dev/rvn0c: 10240 sectors in 3 cylinders of 1 tracks, 4096 sectors 5.0MB in 1 cyl groups (16 c/g, 32.00MB/g, 1280 i/g) super-block backups (for fsck -b #) at: 32 &prompt.root; mount /dev/vn0c /mnt &prompt.root; df /mnt Filesystem 1K-blocks Used Avail Capacity Mounted on /dev/vn0c 4927 1 4532 0% /mnt md: Memory Filesystem disksmemory md is a simple, efficient means to do memory filesystems. Simply take a filesystem you've prepared with, for example, &man.vnconfig.8;, and: md memory disk &prompt.root; dd if=newimage of=/dev/md0 5120+0 records in 5120+0 records out &prompt.root; mount /dev/md0c /mnt &prompt.root; df /mnt Filesystem 1K-blocks Used Avail Capacity Mounted on /dev/md0c 4927 1 4532 0% /mnt Disk Quotas accountingdisk space disk quotas Quotas are an optional feature of the operating system that allow you to limit the amount of disk space and/or the number of files a user, or members of a group, may allocate on a per-file system basis. This is used most often on timesharing systems where it is desirable to limit the amount of resources any one user or group of users may allocate. This will prevent one user from consuming all of the available disk space. Configuring Your System to Enable Disk Quotas Before attempting to use disk quotas it is necessary to make sure that quotas are configured in your kernel. This is done by adding the following line to your kernel configuration file: options QUOTA The stock GENERIC kernel does not have this enabled by default, so you will have to configure, build and install a custom kernel in order to use disk quotas. Please refer to the Configuring the FreeBSD Kernel section for more information on kernel configuration. Next you will need to enable disk quotas in /etc/rc.conf. This is done by adding the line: enable_quotas=YES disk quotaschecking For finer control over your quota startup, there is an additional configuration variable available. Normally on bootup, the quota integrity of each file system is checked by the quotacheck program. The quotacheck facility insures that the data in the quota database properly reflects the data on the file system. This is a very time consuming process that will significantly affect the time your system takes to boot. If you would like to skip this step, a variable is made available for the purpose: check_quotas=NO If you are running FreeBSD prior to 3.2-RELEASE, the configuration is simpler, and consists of only one variable. Set the following in your /etc/rc.conf: check_quotas=YES Finally you will need to edit /etc/fstab to enable disk quotas on a per-file system basis. This is where you can either enable user or group quotas or both for all of your file systems. To enable per-user quotas on a file system, add the userquota option to the options field in the /etc/fstab entry for the file system you want to enable quotas on. For example: /dev/da1s2g /home ufs rw,userquota 1 2 Similarly, to enable group quotas, use the groupquota option instead of the userquota keyword. To enable both user and group quotas, change the entry as follows: /dev/da1s2g /home ufs rw,userquota,groupquota 1 2 By default the quota files are stored in the root directory of the file system with the names quota.user and quota.group for user and group quotas respectively. See man fstab for more information. Even though that man page says that you can specify an alternate location for the quota files, this is not recommended because the various quota utilities do not seem to handle this properly. At this point you should reboot your system with your new kernel. /etc/rc will automatically run the appropriate commands to create the initial quota files for all of the quotas you enabled in /etc/fstab, so there is no need to manually create any zero length quota files. In the normal course of operations you should not be required to run the quotacheck, quotaon, or quotaoff commands manually. However, you may want to read their man pages just to be familiar with their operation. Setting Quota Limits disk quotaslimits Once you have configured your system to enable quotas, verify that they really are enabled. An easy way to do this is to run: &prompt.root; quota -v You should see a one line summary of disk usage and current quota limits for each file system that quotas are enabled on. You are now ready to start assigning quota limits with the edquota command. You have several options on how to enforce limits on the amount of disk space a user or group may allocate, and how many files they may create. You may limit allocations based on disk space (block quotas) or number of files (inode quotas) or a combination of both. Each of these limits are further broken down into two categories; hard and soft limits. hard limit A hard limit may not be exceeded. Once a user reaches his hard limit he may not make any further allocations on the file system in question. For example, if the user has a hard limit of 500 blocks on a file system and is currently using 490 blocks, the user can only allocate an additional 10 blocks. Attempting to allocate an additional 11 blocks will fail. soft limit Soft limits, on the other hand, can be exceeded for a limited amount of time. This period of time is known as the grace period, which is one week by default. If a user stays over his or her soft limit longer than the grace period, the soft limit will turn into a hard limit and no further allocations will be allowed. When the user drops back below the soft limit, the grace period will be reset. The following is an example of what you might see when you run the edquota command. When the edquota command is invoked, you are placed into the editor specified by the EDITOR environment variable, or in the vi editor if the EDITOR variable is not set, to allow you to edit the quota limits. &prompt.root; edquota -u test Quotas for user test: /usr: blocks in use: 65, limits (soft = 50, hard = 75) inodes in use: 7, limits (soft = 50, hard = 60) /usr/var: blocks in use: 0, limits (soft = 50, hard = 75) inodes in use: 0, limits (soft = 50, hard = 60) You will normally see two lines for each file system that has quotas enabled. One line for the block limits, and one line for inode limits. Simply change the value you want updated to modify the quota limit. For example, to raise this users block limit from a soft limit of 50 and a hard limit of 75 to a soft limit of 500 and a hard limit of 600, change: /usr: blocks in use: 65, limits (soft = 50, hard = 75) to: /usr: blocks in use: 65, limits (soft = 500, hard = 600) The new quota limits will be in place when you exit the editor. Sometimes it is desirable to set quota limits on a range of uids. This can be done by use of the option on the edquota command. First, assign the desired quota limit to a user, and then run edquota -p protouser startuid-enduid. For example, if user test has the desired quota limits, the following command can be used to duplicate those quota limits for uids 10,000 through 19,999: &prompt.root; edquota -p test 10000-19999 See man edquota for more detailed information. Checking Quota Limits and Disk Usage disk quotaschecking You can use either the quota or the repquota commands to check quota limits and disk usage. The quota command can be used to check individual user and group quotas and disk usage. Only the super-user may examine quotas and usage for other users, or for groups that they are not a member of. The repquota command can be used to get a summary of all quotas and disk usage for file systems with quotas enabled. The following is some sample output from the quota -v command for a user that has quota limits on two file systems. Disk quotas for user test (uid 1002): Filesystem blocks quota limit grace files quota limit grace /usr 65* 50 75 5days 7 50 60 /usr/var 0 50 75 0 50 60 grace period On the /usr file system in the above example this user is currently 15 blocks over the soft limit of 50 blocks and has 5 days of the grace period left. Note the asterisk * which indicates that the user is currently over his quota limit. Normally file systems that the user is not using any disk space on will not show up in the output from the quota command, even if he has a quota limit assigned for that file system. The option will display those file systems, such as the /usr/var file system in the above example. Quotas over NFS NFS Quotas are enforced by the quota subsystem on the NFS server. The &man.rpc.rquotad.8; daemon makes quota information available to the &man.quota.1; command on NFS clients, allowing users on those machines to see their quota statistics. Enable rpc.rquotad in /etc/inetd.conf like so: rquotad/1 dgram rpc/udp wait root /usr/libexec/rpc.rquotad rpc.rquotad Now restart inetd: &prompt.root; kill -HUP `cat /var/run/inetd.pid` Creating CDs CDROMscreating Contributed by Mike Meyer mwm@mired.org, April 2001. Introduction CDs have a number of features that differentiate them from conventional disks. Initially, they weren't writable by the user. They are designed so that they can be read continuously without delays to move the head between tracks. They are also much easier to transport between systems than similarly sized media were at the time. CDs do have tracks, but this refers to a section of data to be read continuously and not a physical property of the disk. To produce a CD on FreeBSD, you prepare the data files that are going to make up the tracks on the CD, then write the tracks to the CD. ISO 9660 filesystemsISO-9660 The ISO 9660 file system was designed to deal with these differences. It unfortunately codifies file system limits that were common then. Fortunately, it provides an extension mechanism that allows properly written CDs to exceed those limits while still working with systems that do not support those extensions. mkisofs The mkisofs program is used to produce a data file containing an ISO 9660 file system. It has options that support various extensions, and is described below. You can install it with the /usr/ports/sysutils/mkisofs port. CD burnerATAPI Which tool to use to burn the CD depends on whether your CD burner is ATAPI or something else. ATAPI CD burners use the burncd program that is part of the base system. SCSI and USB CD burners should use the cdrecord from the /usr/ports/sysutils/cdrecord port. mkisofs mkisofs produces an ISO 9660 file system that is an image of a directory tree in the Unix file system name space. The simplest usage is: &prompt.root; mkisofs imagefile.iso /path/to/tree filesystemsISO-9660 This command will create an imagefile containing an ISO 9660 file system that is a copy of the tree at /path/to/tree. In the process, it will map the file names to names that fit the limitations of the standard ISO 9660 file system, and will exclude files that have names uncharacteristic of ISO file systems. Read &man.mkisofs.8; for details of this process, and options that can be used to control it. filesystemsHFS filesystemsJoliet A number of options are available to overcome those restrictions. In particular, enables the Rock Ridge extensions common to Unix systems, enables Joliet extensions used by Microsoft systems, and can be used to create HFS file systems used by Macs. Read &man.mkisofs.8; for more information on the last two. For CDs that are going to be used only on FreeBSD systems, can be used to disable all filename restrictions. When used with , it produces a file system image that is identical to the FreeBSD tree you started from, though it may violate the ISO 9660 standard in a number of ways. CDROMscreating bootable The last option of general use is . This is used to specify the location of the boot image for use in producing an El Torito bootable CD. This option takes an argument which is the path to a boot image from the top of the tree being written to the CD. So, given that /tmp/myboot holds a bootable FreeBSD system with the boot image in /tmp/myboot/boot/cdboot, you could produce the image of an ISO 9660 file system in /tmp/bootable.iso like so: &prompt.root; mkisofs boot/cdboot /tmp/bootable.iso /tmp/myboot Having done that, if you have vn configured in your kernel, you can mount the file system with: &prompt.root; vnconfig vn0c /tmp/bootable.iso &prompt.root; mount cd9660 /dev/vn0c /mnt At which point you can verify that /mnt and /tmp/myboot are identical. There are many other options you can use with mkisofs to fine-tune its behavior. See &man.mkisofs.8; for details. burncd CDROMsburning If you have an ATAPI CD burner, you can use the burncd command to burn an ISO image onto a CD. burncd is part of the base system, installed as /usr/sbin/burncd. Usage is very simple, as it has few options: &prompt.root; burncd cddevice data imagefile.iso fixate Will burn a copy of imagefile.iso on cddevice. The default device is /dev/acd0. See &man.burncd.8; for options to set the write speed, eject the CD after burning, and write audio data. cdrecord If you do not have an ATAPI CD burner, you will have to use cdrecord to burn your CDs. cdrecord is not part of the base system; you must install it from either the port at /usr/ports/sysutils/cdrecord or the appropriate package. Changes to the base system can cause binary versions of this program to fail, possibly resulting in a coaster. You should therefore either upgrade the port when you upgrade your system, or if you are tracking -stable, upgrade the port when a new version becomes available. While cdrecord has many options, basic usage is even simpler than burncd. Burning an ISO 9660 image is done with: &prompt.root; cdrecord device imagefile.iso The tricky part of using cdrecord is finding the to use. To find the proper setting, use the flag of cdrecord, which might produce results like this: CDROMsburning &prompt.root; cdrecord Cdrecord 1.9 (i386-unknown-freebsd4.2) Copyright (C) 1995-2000 Jörg Schilling Using libscg version 'schily-0.1' scsibus0: 0,0,0 0) 'SEAGATE ' 'ST39236LW ' '0004' Disk 0,1,0 1) 'SEAGATE ' 'ST39173W ' '5958' Disk 0,2,0 2) * 0,3,0 3) 'iomega ' 'jaz 1GB ' 'J.86' Removable Disk 0,4,0 4) 'NEC ' 'CD-ROM DRIVE:466' '1.26' Removable CD-ROM 0,5,0 5) * 0,6,0 6) * 0,7,0 7) * scsibus1: 1,0,0 100) * 1,1,0 101) * 1,2,0 102) * 1,3,0 103) * 1,4,0 104) * 1,5,0 105) 'YAMAHA ' 'CRW4260 ' '1.0q' Removable CD-ROM 1,6,0 106) 'ARTEC ' 'AM12S ' '1.06' Scanner 1,7,0 107) * This lists the appropriate value for the devices on the list. Locate your CD burner, and use the three numbers separated by commas as the value for . In this case, the CRW device is 1,5,0, so the appropriate input would be =1,5,0. There are easier ways to specify this value; see &man.cdrecord.1; for details. That is also the place to look for information on writing audio tracks, controlling the speed, and other things. diff --git a/en_US.ISO8859-1/books/handbook/introduction/chapter.sgml b/en_US.ISO8859-1/books/handbook/introduction/chapter.sgml index 4769369620..7e318a99b1 100644 --- a/en_US.ISO8859-1/books/handbook/introduction/chapter.sgml +++ b/en_US.ISO8859-1/books/handbook/introduction/chapter.sgml @@ -1,804 +1,838 @@ Restructured, reorganized, and parts rewritten by &a.jim;, 17 January 2000. Introduction Synopsis Thank you for your interest in FreeBSD! The following chapter covers various items about the FreeBSD Project, such as its history, goals, development model, and so on. 4.4BSD-Lite FreeBSD is a 4.4BSD-Lite based operating system for the Intel architecture (x86) and DEC Alpha based systems. Ports to other architectures are also underway. For a brief overview of FreeBSD, see the next section. You can also read about the history of FreeBSD, or the current release. If you are interested in contributing something to the Project (code, hardware, unmarked bills), see the contributing to FreeBSD section. Welcome to FreeBSD! Since you are still here reading this, you most likely have some idea as to what FreeBSD is and what it can do for you. If you are new to FreeBSD, read on for more information. What is FreeBSD? Intel architecture (x86) DEC Alpha architecture In general, FreeBSD is a state-of-the-art operating system based on 4.4BSD-Lite. It runs on computer systems based on the Intel architecture (x86), and also the DEC Alpha architecture. FreeBSD is used to power some of the biggest sites on the Internet, including: Yahoo! Yahoo! Hotmail Hotmail Apache Apache Be, Inc. Be, Inc. Blue Mountain Arts Blue Mountain Arts Pair Networks Pair Networks Whistle Communications Whistle Communications BSDi BSDi and many more. What can FreeBSD do? FreeBSD has many noteworthy features. Some of these are: + preemptive multitasking Preemptive multitasking with - preemptive multitasking dynamic priority adjustment to ensure smooth and fair sharing of the computer between applications and users, even under the heaviest of loads. - + + multi-user facilities Multi-user facilities which allow many - multi-user facilities people to use a FreeBSD system simultaneously for a variety of things. This means, for example, that system peripherals such as printers and tape drives are properly shared between all users on the system or the network and that individual resource limits can be placed on users or groups of users, protecting critical system resources from over-use. + TCP/IP networking Strong TCP/IP networking with - TCP/IP networking support for industry standards such as SLIP, PPP, NFS, DHCP, and NIS. This means that your FreeBSD machine can inter-operate easily with other systems as well as act as an enterprise server, providing vital functions such as NFS (remote file access) and e-mail services or putting your organization on the Internet with WWW, FTP, routing and firewall (security) services. - + + memory protection Memory protection ensures that - memory protection applications (or users) cannot interfere with each other. One application crashing will not affect others in any way. FreeBSD is a 32-bit operating system (64-bit on the Alpha) and was designed as such from the ground up. - + + X-Windows The industry standard X Window System - X-Windows (X11R6) provides a graphical user interface (GUI) for the cost of a common VGA card and monitor and comes with full sources. + + binary compatibility + Linux + + + binary compatibility + SCO + + + binary compatibility + SVR4 + + + binary compatibility + BSD/OS + + + binary compatibility + NetBSD + Binary compatibility with many - binary compatibility - Linux - binary compatibility - SCO - binary compatibility - SVR4 - binary compatibility - BSD/OS - binary compatibility - NetBSD programs built for Linux, SCO, SVR4, BSDI and NetBSD. Thousands of ready-to-run applications are available from the FreeBSD ports and packages collection. Why search the net when you can find it all right here? Thousands of additional and easy-to-port applications are available on the Internet. FreeBSD is source code compatible with most popular commercial Unix systems and thus most applications require few, if any, changes to compile. + virtual memory Demand paged virtual memory and - virtual memory merged VM/buffer cache design efficiently satisfies applications with large appetites for memory while still maintaining interactive response to other users. + + Symetric Multi-Processing (SMP) + SMP support for machines with - Symetric Multi-Processing (SMP) multiple CPUs (Intel only). + + compilers + C + + + compilers + C++ + + + compilers + Fortran + A full complement of C, - compilers - C - compilers - C++ - compilers - Fortran C++, Fortran, and Perl development tools. Many additional languages for advanced research and development are also available in the ports and packages collection. - + + source code Source code for the entire system - source code means you have the greatest degree of control over your environment. Why be locked into a proprietary solution at the mercy of your vendor when you can have a truly Open System? Extensive on-line documentation. And many more! - FreeBSD is based on the 4.4BSD-Lite release from Computer 4.4BSD-Lite - Computer Systems Resarch Group - (CSRG) + + Computer Systems Resarch Group (CSRG) + U.C. Berkeley + FreeBSD is based on the 4.4BSD-Lite release from Computer Systems Research Group (CSRG) at the University of California at Berkeley, and carries on the distinguished tradition of BSD systems development. In addition to the fine work provided by CSRG, the FreeBSD Project has put in many thousands of hours in fine tuning the system for maximum performance and reliability in real-life load situations. As many of the commercial giants struggle to field PC operating systems with such features, performance and reliability, FreeBSD can offer them now! The applications to which FreeBSD can be put are truly limited only by your own imagination. From software development to factory automation, inventory control to azimuth correction of remote satellite antennae; if it can be done with a commercial UNIX product then it is more than likely that you can do it with FreeBSD, too! FreeBSD also benefits significantly from the literally thousands of high quality applications developed by research centers and universities around the world, often available at little to no cost. Commercial applications are also available and appearing in greater numbers every day. Because the source code for FreeBSD itself is generally available, the system can also be customized to an almost unheard of degree for special applications or projects, and in ways not generally possible with operating systems from most major commercial vendors. Here is just a sampling of some of the applications in which people are currently using FreeBSD: Internet Services: The robust TCP/IP networking built into FreeBSD makes it an ideal platform for a variety of Internet services such as: + FTP servers - FTP servers - FTP servers + FTP servers + web servers World Wide Web servers (standard or secure - [SSL]) - web servers + [SSL]) - + + firewalls + IP masquerading Firewalls and NAT (IP masquerading) - gateways. - firewalls - IP masquerading + gateways. + electronic mail - Electronic Mail servers - electronic mail - + Electronic Mail servers + USENET - USENET News or Bulletin Board Systems - USENET + USENET News or Bulletin Board Systems And more... With FreeBSD, you can easily start out small with an inexpensive 386 class PC and upgrade all the way up to a quad-processor Xeon with RAID storage as your enterprise grows. Education: Are you a student of computer science or a related engineering field? There is no better way of learning about operating systems, computer architecture and networking than the hands on, under the hood experience that FreeBSD can provide. A number of freely available CAD, mathematical and graphic design packages also make it highly useful to those whose primary interest in a computer is to get other work done! Research: With source code for the entire system available, FreeBSD is an excellent platform for research in operating systems as well as other branches of computer science. FreeBSD's freely available nature also makes it possible for remote groups to collaborate on ideas or shared development without having to worry about special licensing agreements or limitations on what may be discussed in open forums. + router + DNS Server Networking: Need a new router? A - router - DNS Server name server (DNS)? A firewall to keep people out of your internal network? FreeBSD can easily turn that unused 386 or 486 PC sitting in the corner into an advanced router with sophisticated packet-filtering capabilities. + + X-Windows + XFree86 + + + X-Windows + Accellerated-X + X Window workstation: FreeBSD is a - X-Windows - XFree86 - X-Windows - Accellerated-X fine choice for an inexpensive X terminal solution, either using the freely available XFree86 server or one of the excellent commercial servers provided by X Inside. Unlike an X terminal, FreeBSD allows many applications to be run locally, if desired, thus relieving the burden on a central server. FreeBSD can even boot diskless, making individual workstations even cheaper and easier to administer. + GNU Compiler Collection Software Development: The basic - GNU Compiler Collection FreeBSD system comes with a full complement of development tools including the renowned GNU C/C++ compiler and debugger. FreeBSD is available in both source and binary form on CDROM and via anonymous FTP. See Obtaining FreeBSD for more details. About the FreeBSD Project The following section provides some background information on the project, including a brief history, project goals, and the development model of the project. A Brief History of FreeBSD Contributed by &a.jkh;. 386BSD Patchkit Hubbard, Jordan Williams, Nate Grimes, Rod - FreeBSD Project - History + + FreeBSD Project + History + The FreeBSD project had its genesis in the early part of 1993, partially as an outgrowth of the Unofficial 386BSD Patchkit by the patchkit's last 3 coordinators: Nate Williams, Rod Grimes and myself. 386BSD Our original goal was to produce an intermediate snapshot of 386BSD in order to fix a number of problems with it that the patchkit mechanism just was not capable of solving. Some of you may remember the early working title for the project being 386BSD 0.5 or 386BSD Interim in reference to that fact. Jolitz, Bill 386BSD was Bill Jolitz's operating system, which had been up to that point suffering rather severely from almost a year's worth of neglect. As the patchkit swelled ever more uncomfortably with each passing day, we were in unanimous agreement that something had to be done and decided to try and assist Bill by providing this interim cleanup snapshot. Those plans came to a rude halt when Bill Jolitz suddenly decided to withdraw his sanction from the project without any clear indication of what would be done instead. Greenman, David Walnut Creek CDROM It did not take us long to decide that the goal remained worthwhile, even without Bill's support, and so we adopted the name FreeBSD, coined by David Greenman. Our initial objectives were set after consulting with the system's current users and, once it became clear that the project was on the road to perhaps even becoming a reality, I contacted Walnut Creek CDROM with an eye towards improving FreeBSD's distribution channels for those many unfortunates without easy access to the Internet. Walnut Creek CDROM not only supported the idea of distributing FreeBSD on CD but also went so far as to provide the project with a machine to work on and a fast Internet connection. Without Walnut Creek CDROM's almost unprecedented degree of faith in what was, at the time, a completely unknown project, it is quite unlikely that FreeBSD would have gotten as far, as fast, as it has today. 4.3BSD-Lite Net/2 U.C. Berkeley 386BSD Free Software Foundation The first CDROM (and general net-wide) distribution was FreeBSD 1.0, released in December of 1993. This was based on the 4.3BSD-Lite (Net/2) tape from U.C. Berkeley, with many components also provided by 386BSD and the Free Software Foundation. It was a fairly reasonable success for a first offering, and we followed it with the highly successful FreeBSD 1.1 release in May of 1994. Novell U.C. Berkeley Net/2 - AT&T + AT&amp;T Around this time, some rather unexpected storm clouds formed on the horizon as Novell and U.C. Berkeley settled their long-running lawsuit over the legal status of the Berkeley Net/2 tape. A condition of that settlement was U.C. Berkeley's concession that large parts of Net/2 were encumbered code and the property of Novell, who had in turn acquired it from AT&T some time previously. What Berkeley got in return was Novell's blessing that the 4.4BSD-Lite release, when it was finally released, would be declared unencumbered and all existing Net/2 users would be strongly encouraged to switch. This included FreeBSD, and the project was given until the end of July 1994 to stop shipping its own Net/2 based product. Under the terms of that agreement, the project was allowed one last release before the deadline, that release being FreeBSD 1.1.5.1. FreeBSD then set about the arduous task of literally re-inventing itself from a completely new and rather incomplete set of 4.4BSD-Lite bits. The Lite releases were light in part because Berkeley's CSRG had removed large chunks of code required for actually constructing a bootable running system (due to various legal requirements) and the fact that the Intel port of 4.4 was highly incomplete. It took the project until November of 1994 to make this transition, at which point it released FreeBSD 2.0 to the net and on CDROM (in late December). Despite being still more than a little rough around the edges, the release was a significant success and was followed by the more robust and easier to install FreeBSD 2.0.5 release in June of 1995. We released FreeBSD 2.1.5 in August of 1996, and it appeared to be popular enough among the ISP and commercial communities that another release along the 2.1-STABLE branch was merited. This was FreeBSD 2.1.7.1, released in February 1997 and capping the end of mainstream development on 2.1-STABLE. Now in maintenance mode, only security enhancements and other critical bug fixes will be done on this branch (RELENG_2_1_0). FreeBSD 2.2 was branched from the development mainline (-CURRENT) in November 1996 as the RELENG_2_2 branch, and the first full release (2.2.1) was released in April 1997. Further releases along the 2.2 branch were done in the summer and fall of '97, the last of which (2.2.8) appeared in November 1998. The first official 3.0 release appeared in October 1998 and spelled the beginning of the end for the 2.2 branch. The tree branched again on Jan 20, 1999, leading to the 4.0-CURRENT and 3.X-STABLE branches. From 3.X-STABLE, 3.1 was released on February 15, 1999, 3.2 on May 15, 1999, 3.3 on September 16, 1999, 3.4 on December 20, 1999, and 3.5 on June 24, 2000, which was followed a few days later by a minor point release update to 3.5.1, to incorporate some last-minute security fixes to Kerberos. This will be the final release in the 3.X branch. There was another branch on March 13, 2000, which saw the emergence of the 4.x-STABLE branch, now considered to be the "current -stable branch". There have been several releases from it so far: 4.0-RELEASE came out in March 2000, 4.1 was released in July 2000 and 4.2 in November 2000. There will be more releases along the 4.x-stable (RELENG_4) branch well into 2001. Long-term development projects continue to take place in the 5.0-CURRENT (trunk) branch, and SNAPshot releases of 5.0 on CDROM (and, of course, on the net) are continually made available from the snapshot server as work progresses. FreeBSD Project Goals Contributed by &a.jkh;. - FreeBSD Project - Goals + + FreeBSD Project + Goals + The goals of the FreeBSD Project are to provide software that may be used for any purpose and without strings attached. Many of us have a significant investment in the code (and project) and would certainly not mind a little financial compensation now and then, but we are definitely not prepared to insist on it. We believe that our first and foremost mission is to provide code to any and all comers, and for whatever purpose, so that the code gets the widest possible use and provides the widest possible benefit. This is, I believe, one of the most fundamental goals of Free Software and one that we enthusiastically support. - GNU General Public License (GPL) - GNU Lesser General Public License - (LGPL) + + GNU General Public License (GPL) + + + GNU Lesser General Public License (LGPL) + BSD Copyright That code in our source tree which falls under the GNU General Public License (GPL) or Library General Public License (LGPL) comes with slightly more strings attached, though at least on the side of enforced access rather than the usual opposite. Due to the additional complexities that can evolve in the commercial use of GPL software we do, however, prefer software submitted under the more relaxed BSD copyright when it's a reasonable option to do so. The FreeBSD Development Model Contributed by &a.asami;. - FreeBSD Project - Development Model + + FreeBSD Project + Development Model + The development of FreeBSD is a very open and flexible process, FreeBSD being literally built from the contributions of hundreds of people around the world, as can be seen from our list of contributors. We are constantly on the lookout for new developers and ideas, and those interested in becoming more closely involved with the project need simply contact us at the &a.hackers;. The &a.announce; is also available to those wishing to make other FreeBSD users aware of major areas of work. Useful things to know about the FreeBSD project and its development process, whether working independently or in close cooperation: The CVS repository + CVS Repository + + Concurrent Version System (see CVS repository) + The central source tree for FreeBSD is maintained by - CVS Repository - Concurrent Version System (see CVS repository) CVS (Concurrent Version System), a freely available source code control tool that comes bundled with FreeBSD. The primary CVS repository resides on a machine in Concord CA, USA from where it is replicated to numerous mirror machines throughout the world. The CVS tree, as well as the -CURRENT and -STABLE trees which are checked out of it, can be easily replicated to your own machine as well. Please refer to the Synchronizing your source tree section for more information on doing this. The committers list + committers The committers - committers are the people who have write access to the CVS tree, and are thus authorized to make modifications to the FreeBSD source (the term committer comes from the &man.cvs.1; commit command, which is used to bring new changes into the CVS repository). The best way of making submissions for review by the committers list is to use the &man.send-pr.1; command, though if something appears to be jammed in the system then you may also reach them by sending mail to cvs-committers@FreeBSD.org. The FreeBSD core team + core team The FreeBSD core team - core team would be equivalent to the board of directors if the FreeBSD Project were a company. The primary task of the core team is to make sure the project, as a whole, is in good shape and is heading in the right directions. Inviting dedicated and responsible developers to join our group of committers is one of the functions of the core team, as is the recruitment of new core team members as others move on. The current core team was elected from a pool of committer candidates in October 2000. Elections are held every 2 years. Some core team members also have specific areas of responsibility, meaning that they are committed to ensuring that some large portion of the system works as advertised. Most members of the core team are volunteers when it comes to FreeBSD development and do not benefit from the project financially, so commitment should also not be misconstrued as meaning guaranteed support. The board of directors analogy above is not actually very accurate, and it may be more suitable to say that these are the people who gave up their lives in favor of FreeBSD against their better judgment! ;-) Outside contributors + contributors Last, but definitely not least, the largest group of - contributors developers are the users themselves who provide feedback and bug fixes to us on an almost constant basis. The primary way of keeping in touch with FreeBSD's more non-centralized development is to subscribe to the &a.hackers; (see mailing list info) where such things are discussed. The list of those who have contributed something, which made its way into our source tree, is a long and growing one, so why not join it by contributing something back to FreeBSD today? :-) Providing code is not the only way of contributing to the project; for a more complete list of things that need doing, please refer to the how to contribute section in this handbook. In summary, our development model is organized as a loose set of concentric circles. The centralized model is designed for the convenience of the users of FreeBSD, who are thereby provided with an easy way of tracking one central code base, not to keep potential contributors out! Our desire is to present a stable operating system with a large set of coherent application programs that the users can easily install and use, and this model works very well in accomplishing that. All we ask of those who would join us as FreeBSD developers is some of the same dedication its current people have to its continued success! The Current FreeBSD Release NetBSD OpenBSD 386BSD Free Software Foundation U.C. Berkeley - Computer Systems Resarch Group - (CSRG) + + Computer Systems Resarch Group (CSRG) + FreeBSD is a freely available, full source 4.4BSD-Lite based release for Intel i386, i486, Pentium, Pentium Pro, Celeron, Pentium II, Pentium III (or compatible) and DEC Alpha based computer systems. It is based primarily on software from U.C. Berkeley's CSRG group, with some enhancements from NetBSD, OpenBSD, 386BSD, and the Free Software Foundation. Since our release of FreeBSD 2.0 in late 94, the performance, feature set, and stability of FreeBSD has improved dramatically. The largest change is a revamped virtual memory system with a merged VM/file buffer cache that not only increases performance, but also reduces FreeBSD's memory footprint, making a 5MB configuration a more acceptable minimum. Other enhancements include full NIS client and server support, transaction TCP support, dial-on-demand PPP, integrated DHCP support, an improved SCSI subsystem, ISDN support, support for ATM, FDDI, Fast and Gigabit Ethernet (1000Mbit) adapters, improved support for the latest Adaptec controllers, and many hundreds of bug fixes. We have also taken the comments and suggestions of many of our users to heart and have attempted to provide what we hope is a more sane and easily understood installation process. Your feedback on this (constantly evolving) process is especially welcome! In addition to the base distributions, FreeBSD offers a ported software collection with thousands of commonly sought-after programs. By mid-November 2000, there were over 4000 ports! The list of ports ranges from http (WWW) servers, to games, languages, editors, and almost everything in between. The entire ports collection requires approximately 100MB of storage, all ports being expressed as deltas to their original sources. This makes it much easier for us to update ports, and greatly reduces the disk space demands made by the older 1.0 ports collection. To compile a port, you simply change to the directory of the program you wish to install, type make install, and let the system do the rest. The full original distribution for each port you build is retrieved dynamically off the CDROM or a local FTP site, so you need only enough disk space to build the ports you want. Almost every port is also provided as a pre-compiled package, which can be installed with a simple command (pkg_add) by those who do not wish to compile their own ports from source. A number of additional documents which you may find very helpful in the process of installing and using FreeBSD may now also be found in the /usr/share/doc directory on any machine running FreeBSD 2.1 or later. You may view the locally installed manuals with any HTML capable browser using the following URLs: The FreeBSD Handbook file:/usr/share/doc/handbook/index.html The FreeBSD FAQ file:/usr/share/doc/faq/index.html You can also view the master (and most frequently updated) copies at http://www.FreeBSD.org/. diff --git a/en_US.ISO8859-1/books/handbook/kernelconfig/chapter.sgml b/en_US.ISO8859-1/books/handbook/kernelconfig/chapter.sgml index 03936f1e67..f0580e87e8 100644 --- a/en_US.ISO8859-1/books/handbook/kernelconfig/chapter.sgml +++ b/en_US.ISO8859-1/books/handbook/kernelconfig/chapter.sgml @@ -1,1126 +1,1176 @@ Configuring the FreeBSD Kernel Synopsis Updated and restructured by &a.jim;, March 2000. Originally contributed by &a.jehamby;, 6 October 1995. - kernelbuilding a custom kernel + + kernel + building a custom kernel + + The following chapter of the handbook covers everything you will need to know in order to build a custom kernel. If you are wondering what the benefits of a custom kernel are, or would like to know how to configure, compile, and install a custom kernel, this chapter is for you. Why Build a Custom Kernel? Building a custom kernel is one of the most important rites of passage nearly every UNIX user must endure. This process, while time consuming, will provide many benefits to your FreeBSD system. Unlike the GENERIC kernel, which must support a wide range of hardware, a custom kernel only contains support for your PC's hardware. This has a number of benefits, such as: Faster boot time. Since the kernel will only probe the hardware you have on your system, the time it takes your system to boot will decrease dramatically. Less memory use. A custom kernel often uses less memory than the GENERIC kernel, which is important because the kernel is one process that must always be present in memory. For this reason, a custom kernel is especially useful on a system with a small amount of RAM. Additional hardware support. A custom kernel allows you to add in support for devices such as sound cards, which are not present in the GENERIC kernel. Building and Installing a Custom Kernel - kernelbuilding / installing + + kernel + building / installing + + First, let us take a quick tour of the kernel build directory. All directories mentioned will be relative to the main /usr/src/sys directory, which is also accessible through /sys. There are a number of subdirectories here representing different parts of the kernel, but the most important, for our purposes, are arch/conf, where you will edit your custom kernel configuration, and compile, which is the staging area where your kernel will be built. arch represents either i386, alpha, or pc98 (an alternative development branch of PC hardware, popular in Japan). Everything inside a particular architecture's directory deals with that architecture only; the rest of the code is common to all platforms to which FreeBSD could potentially be ported. Notice the logical organization of the directory structure, with each supported device, filesystem, and option in its own subdirectory. If there is not a /usr/src/sys directory on your system, then the kernel source has not been installed. The easiest way to do this is by running /stand/sysinstall as root, choosing Configure, then Distributions, then src, then sys. Next, move to the arch/conf directory and copy the GENERIC configuration file to the name you want to give your kernel. For example: &prompt.root; cd /usr/src/sys/i386/conf &prompt.root; cp GENERIC MYKERNEL Traditionally, this name is in all capital letters and, if you are maintaining multiple FreeBSD machines with different hardware, it is a good idea to name it after your machine's hostname. We will call it MYKERNEL for the purpose of this example. You must execute these and all of the following commands under the root account or you will get permission denied errors. Now, edit MYKERNEL with your favorite text editor. If you are just starting out, the only editor available will probably be vi, which is too complex to explain here, but is covered well in many books in the bibliography. However, FreeBSD does offer an easier editor called ee which, if you are a beginner, should be your editor of choice. Feel free to change the comment lines at the top to reflect your configuration or the changes you have made to differentiate it from GENERIC. - SunOS + If you have built a kernel under SunOS or some other BSD operating system, much of this file will be very familiar to you. If you are coming from some other operating system such as DOS, on the other hand, the GENERIC configuration file might seem overwhelming to you, so follow the descriptions in the Configuration File section slowly and carefully. Be sure to always check the file /usr/src/UPDATING, before you perform any update steps, in the case you sync your source-tree with the latest sources of the FreeBSD project. In this file all important issues with updating FreeBSD are written down. /usr/src/UPDATING always fits to your version of the FreeBSD source, and is therefore more accurate for those information than the handbook. When you are finished, type the following to compile and install your kernel if you are using FreeBSD prior FreeBSD 4.0 and don't want to upgrade to FreeBSD 4.0 or higher with this step, or if you are using a release-version of FreeBSD and your /usr/src/ directory only contains the sys/ sub-directory. If you are trying to upgrade your kernel from an older version of FreeBSD, you will probably have to get a new version of &man.config.8; from the same place you got the new kernel sources. It is located in /usr/src/usr.sbin, so you will need to download those sources as well. Re-build and install it before running the next commands. &prompt.root; /usr/sbin/config MYKERNEL &prompt.root; cd ../../compile/MYKERNEL &prompt.root; make depend &prompt.root; make &prompt.root; make install If you have just upgraded to a newer version of 4.X or higher (ie from 3.X to 4-STABLE, or even from 4-STABLE to a later version of 4-STABLE), make sure you have built the world, and then run the following commands: &prompt.root; cd /usr/src &prompt.root; make buildkernel KERNCONF=MYKERNEL &prompt.root; make installkernel KERNCONF=MYKERNEL In FreeBSD 4.2 and older you must replace KERCONF= with KERNEL=. 4.2-STABLE that was fetched after Feb 2nd, 2001 does recognize KERNCONF= CVSup anoncvs - CVSanonymous CTM + + CVS + anonymous + + If you have not upgraded your source tree in any way (you have not run CVSup, CTM, or used anoncvs), then you should use the config, make depend, make, make install sequence. If you have upgraded your sources since your last kernel build, you must use the make buildkernel method to build your kernel. Otherwise, old utilities will be used to build the kernel, which will probably fail. Do not use the config/make sequence to build your kernel if you have updated the sources! kernel.old + The new kernel will be copied to the root directory as /kernel and the old kernel will be moved to /kernel.old. Now, shutdown the system and reboot to use your kernel. In case something goes wrong, there are some troubleshooting instructions at the end of this document. Be sure to read the section which explains how to recover in case your new kernel does not boot. If you have added any new devices (such as sound cards) you may have to add some device nodes to your /dev directory before you can use them. The Configuration File - kernelconfig file kernelLINT LINT + + kernel + config file + + The general format of a configuration file is quite simple. Each line contains a keyword and one or more arguments. For simplicity, most lines only contain one argument. Anything following a # is considered a comment and ignored. The following sections describe each keyword, generally in the order they are listed in GENERIC, although some related keywords have been grouped together in a single section (such as Networking) even though they are actually scattered throughout the GENERIC file. An exhaustive list of options and more detailed explanations of the device lines is present in the LINT configuration file, located in the same directory as GENERIC. If you are in doubt as to the purpose or necessity of a line, check first in LINT. Quoting numbers In all versions of FreeBSD up to and including 3.X, &man.config.8; required that any strings in the configuration file that contained numbers used as text had to be enclosed in double quotes. This requirement was removed in the 4.X branch, which this book covers, so if you are on a pre-4.X system, see the /usr/src/sys/i386/conf/LINT and /usr/src/sys/i386/conf/GENERIC files on your system for examples. + + kernel + example config + - kernelexample config The following is an example GENERIC kernel configuration file with various additional comments where needed for clarity. This example should match your copy in /usr/src/sys/i386/conf/GENERIC fairly closely. For details of all the possible kernel options, see /usr/src/sys/i386/conf/LINT. # # GENERIC -- Generic kernel configuration file for FreeBSD/i386 # # For more information on this file, please read the handbook section on # Kernel Configuration Files: # # http://www.freebsd.org/handbook/kernelconfig-config.html # # The handbook is also available locally in /usr/share/doc/handbook # if you've installed the doc distribution, otherwise always see the # FreeBSD World Wide Web server (http://www.FreeBSD.ORG/) for the # latest information. # # An exhaustive list of options and more detailed explanations of the # device lines is also present in the ./LINT configuration file. If you are # in doubt as to the purpose or necessity of a line, check first in LINT. # # $FreeBSD: src/sys/i386/conf/GENERIC,v 1.246 2000/03/09 16:32:55 jlemon Exp $ The following are the mandatory keywords required in every kernel you build: + + kernel options + machine + - kernel optionsmachine machine i386 This is the machine architecture. It must be either i386, alpha, or pc98. - kernel optionscpu + + kernel options + cpu + cpu I386_CPU cpu I486_CPU cpu I586_CPU cpu I686_CPU The above specifies the type of CPU you have in your system. You may have multiple instances of the CPU line (i.e., you are not sure whether you should use I586_CPU or I686_CPU), however, for a custom kernel, it is best to specify only the CPU you have. If you are unsure which type your CPU use, you can use the dmesg command to view your boot up messages. + + kernel options + cpu type + - kernel optionscpu type The Alpha architecture has different values for cpu_type. They include: cpu EV4 cpu EV5 If you are using an Alpha machine, you should be using one of the above CPU types. + + kernel options + ident + - kernel optionsident ident GENERIC This is the identification of the kernel. You should change this to whatever you named your kernel, in our previous example, MYKERNEL. The value you put in the ident string will print when you boot up the kernel, so it is useful to give a kernel a different name if you want to keep it separate from your usual kernel (i.e., you want to build an experimental kernel). + + kernel options + maxusers + - kernel optionsmaxusers maxusers 32 The maxusers option sets the size of a number of important system tables. This number is supposed to be roughly equal to the number of simultaneous users you expect to have on your machine. However, under normal circumstances, you will want to set maxusers to at least 4, especially if you are using the X Window System or compiling software. The reason is that the most important table set by maxusers is the maximum number of processes, which is set to 20 + 16 * maxusers, so if you set maxusers to 1, then you can only have 36 simultaneous processes, including the 18 or so that the system starts up at boot time, and the 15 or so you will probably create when you start the X Window System. Even a simple task like reading a man page will start up nine processes to filter, decompress, and view it. Setting maxusers to 64 will allow you to have up to 1044 simultaneous processes, which should be enough for nearly all uses. If, however, you see the dreaded proc table full error when trying to start another program, or are running a server with a large number of simultaneous users (like ftp.FreeBSD.org), you can always increase the number and rebuild. maxusers does not limit the number of users which can log into your machine. It simply sets various table sizes to reasonable values considering the maximum number of users you will likely have on your system and how many processes each of them will be running. One keyword which does limit the number of simultaneous remote logins is pseudo-device pty 16. Everything that follows is more or less optional. See the notes underneath or next to each option for more information. #makeoptions DEBUG=-g #Build kernel with gdb(1) debug symbols options MATH_EMULATE #Support for x87 emulation This line allows the kernel to simulate a math co-processor if your computer does not have one (386 or 486SX). If you have a 486DX, or a 386 or 486SX (with a separate 387 or 487 chip), or higher (Pentium, Pentium II, etc.), you can comment this line out. The normal math co-processor emulation routines that come with FreeBSD are not very accurate. If you do not have a math co-processor, and you need the best accuracy, it is recommended that you change this option to GPL_MATH_EMULATION to use the GNU math support, which is not included by default for licensing reasons. options INET #InterNETworking Networking support. Leave this in, even if you do not plan to be connected to a network. Most programs require at least loopback networking (i.e., making network connections within your PC), so this is essentially mandatory. options INET6 #IPv6 communications protocols This enables the IPv6 communication protocols. options FFS #Berkeley Fast Filesystem options FFS_ROOT #FFS usable as root device [keep this!] This is the basic hard drive filesystem. Leave it in if you boot from the hard disk. options MFS #Memory Filesystem options MD_ROOT #MD is a potential root device This is the memory-mapped filesystem. This is basically a RAM disk for fast storage of temporary files, useful if you have a lot of swap space that you want to take advantage of. A perfect place to mount an MFS partition is on the /tmp directory, since many programs store temporary data here. To mount an MFS RAM disk on /tmp, add the following line to /etc/fstab: /dev/ad1s2b /tmp mfs rw 0 0 Now you simply need to either reboot, or run the command mount /tmp. - kernel optionsNFS - kernel optionsNFS_ROOT + + kernel options + NFS + + + kernel options + NFS_ROOT + options NFS #Network Filesystem options NFS_ROOT #NFS usable as root device, NFS required The network filesystem. Unless you plan to mount partitions from a UNIX file server over TCP/IP, you can comment these out. - kernel optionsMSDOSFS + + kernel options + MSDOSFS + options MSDOSFS #MSDOS Filesystem The MS-DOS filesystem. Unless you plan to mount a DOS formatted hard drive partition at boot time, you can safely comment this out. It will be automatically loaded the first time you mount a DOS partition, as described above. Also, the excellent mtools software (in the ports collection) allows you to access DOS floppies without having to mount and unmount them (and does not require MSDOSFS at all). options CD9660 #ISO 9660 Filesystem options CD9660_ROOT #CD-ROM usable as root, CD9660 required The ISO 9660 filesystem for CDROMs. Comment it out if you do not have a CDROM drive or only mount data CDs occasionally (since it will be dynamically loaded the first time you mount a data CD). Audio CDs do not need this filesystem. options PROCFS #Process filesystem The process filesystem. This is a pretend filesystem mounted on /proc which allows programs like &man.ps.1; to give you more information on what processes are running. options COMPAT_43 #Compatible with BSD 4.3 [KEEP THIS!] Compatibility with 4.3BSD. Leave this in; some programs will act strangely if you comment this out. options SCSI_DELAY=15000 #Delay (in ms) before probing SCSI This causes the kernel to pause for 15 seconds before probing each SCSI device in your system. If you only have IDE hard drives, you can ignore this, otherwise you will probably want to lower this number, perhaps to 5 seconds, to speed up booting. Of course, if you do this, and FreeBSD has trouble recognizing your SCSI devices, you will have to raise it back up. options UCONSOLE #Allow users to grab the console Allow users to grab the console, which is useful for X users. For example, you can create a console xterm by typing xterm -C, which will display any write, talk, and any other messages you receive, as well as any console messages sent by the kernel. options USERCONFIG #boot -c editor This option allows you to boot the configuration editor from the boot menu. options VISUAL_USERCONFIG #visual boot -c editor This option allows you to boot the visual configuration editor from the boot menu. options KTRACE #ktrace(1) support This enables kernel process tracing, which is useful in debugging. options SYSVSHM #SYSV-style shared memory This option provides for System V shared memory. The most common use of this is the XSHM extension in X, which many graphics-intensive programs will automatically take advantage of for extra speed. If you use X, you'll definitely want to include this. options SYSVSEM #SYSV-style semaphores Support for System V semaphores. Less commonly used but only adds a few hundred bytes to the kernel. options SYSVMSG #SYSV-style message queues Support for System V messages. Again, only adds a few hundred bytes to the kernel. The &man.ipcs.1; command will list any processes using each of these System V facilities. options P1003_1B #Posix P1003_1B real-time extensions options _KPOSIX_PRIORITY_SCHEDULING Real-time extensions added in the 1993 POSIX. Certain applications in the ports collection use these (such as Star Office). - kernel optionsICMP_BANDLIM + + kernel options + ICMP_BANDLIM + options ICMP_BANDLIM #Rate limit bad replies This option enables ICMP error response bandwidth limiting. You typically want this option as it will help protect the machine from denial of service packet attacks. - kernel optionsSMP + + kernel options + SMP + # To make an SMP kernel, the next two are needed #options SMP # Symmetric MultiProcessor Kernel #options APIC_IO # Symmetric (APIC) I/O The above are both required for SMP support. device isa All PCs supported by FreeBSD have one of these. If you have an IBM PS/2 (Micro Channel Architecture), you cannot run FreeBSD at this time (support is being worked on). device eisa Include this if you have an EISA motherboard. This enables auto-detection and configuration support for all devices on the EISA bus. device pci Include this if you have a PCI motherboard. This enables auto-detection of PCI cards and gatewaying from the PCI to ISA bus. # Floppy drives device fdc0 at isa? port IO_FD1 irq 6 drq 2 device fd0 at fdc0 drive 0 device fd1 at fdc0 drive 1 This is the floppy drive controller. fd0 is the A: floppy drive, and fd1 is the B: drive. device ata This driver supports all ATA and ATAPI devices. You only need one device ata line for the kernel to detect all PCI ATA/ATAPI devices on modern machines. device atadisk # ATA disk drives This is needed along with device ata for ATAPI disk drives. device atapicd # ATAPI CDROM drives This is needed along with device ata for ATAPI CDROM drives. device atapifd # ATAPI floppy drives This is needed along with device ata for ATAPI floppy drives. device atapist # ATAPI tape drives This is needed along with device ata for ATAPI tape drives. options ATA_STATIC_ID #Static device numbering This makes the controller number static (like the old driver) or else the device numbers are dynamically allocated. # ATA and ATAPI devices device ata0 at isa? port IO_WD1 irq 14 device ata1 at isa? port IO_WD2 irq 15 Use the above for older, non-PCI systems. # SCSI Controllers device ahb # EISA AHA1742 family device ahc # AHA2940 and onboard AIC7xxx devices device amd # AMD 53C974 (Teckram DC-390(T)) device dpt # DPT Smartcache - See LINT for options! device isp # Qlogic family device ncr # NCR/Symbios Logic device sym # NCR/Symbios Logic (newer chipsets) device adv0 at isa? device adw device bt0 at isa? device aha0 at isa? device aic0 at isa? SCSI controllers. Comment out any you do not have in your system. If you have an IDE only system, you can remove these altogether. # SCSI peripherals device scbus # SCSI bus (required) device da # Direct Access (disks) device sa # Sequential Access (tape etc) device cd # CD device pass # Passthrough device (direct SCSI access) SCSI peripherals. Again, comment out any you do not have, or if you have only IDE hardware, you can remove them completely. # RAID controllers device ida # Compaq Smart RAID device amr # AMI MegaRAID device mlx # Mylex DAC960 family Supported RAID controllers. If you do not have any of these, you can comment them out or remove them. # atkbdc0 controls both the keyboard and the PS/2 mouse device atkbdc0 at isa? port IO_KBD The keyboard controller (atkbdc) provides I/O services for the AT keyboard and PS/2 style pointing devices. This controller is required by the keyboard driver (atkbd) and the PS/2 pointing device driver (psm). device atkbd0 at atkbdc? irq 1 The atkbd driver, together with atkbdc controller, provides access to the AT 84 keyboard or the AT enhanced keyboard which is connected to the AT keyboard controller. device psm0 at atkbdc? irq 12 Use this device if your mouse plugs into the PS/2 mouse port. device vga0 at isa? The video card driver. # splash screen/screen saver pseudo-device splash Splash screen at start up! Screen savers require this too. # syscons is the default console driver, resembling an SCO console device sc0 at isa? sc0 is the default console driver, which resembles a SCO console. Since most full-screen programs access the console through a terminal database library like termcap, it should not matter whether you use this or vt0, the VT220 compatible console driver. When you log in, set your TERM variable to scoansi if full-screen programs have trouble running under this console. # Enable this and PCVT_FREEBSD for pcvt vt220 compatible console driver #device vt0 at isa? #options XSERVER # support for X server on a vt console #options FAT_CURSOR # start with block cursor # If you have a ThinkPAD, uncomment this along with the rest of the PCVT lines #options PCVT_SCANSET=2 # IBM keyboards are non-std This is a VT220-compatible console driver, backward compatible to VT100/102. It works well on some laptops which have hardware incompatibilities with sc0. Also set your TERM variable to vt100 or vt220 when you log in. This driver might also prove useful when connecting to a large number of different machines over the network, where termcap or terminfo entries for the sc0 device are often not available — vt100 should be available on virtually any platform. # Floating point support - do not disable. device npx0 at nexus? port IO_NPX irq 13 npx0 is the interface to the floating point math unit in FreeBSD, which is either the hardware co-processor or the software math emulator. This is not optional. # Power management support (see LINT for more options) device apm0 at nexus? disable flags 0x20 # Advanced Power Management Advanced Power Management support. Useful for laptops. # PCCARD (PCMCIA) support device card device pcic0 at isa? irq 10 port 0x3e0 iomem 0xd0000 device pcic1 at isa? irq 11 port 0x3e2 iomem 0xd4000 disable PCMCIA support. You need this if you are installing on a laptop. # Serial (COM) ports device sio0 at isa? port IO_COM1 flags 0x10 irq 4 device sio1 at isa? port IO_COM2 irq 3 device sio2 at isa? disable port IO_COM3 irq 5 device sio3 at isa? disable port IO_COM4 irq 9 These are the four serial ports referred to as COM1 through COM4 in the MS-DOS/Windows world. If you have an internal modem on COM4 and a serial port at COM2, you will have to change the IRQ of the modem to 2 (for obscure technical reasons, IRQ2 = IRQ 9) in order to access it from FreeBSD. If you have a multiport serial card, check the manual page for &man.sio.4; for more information on the proper values for these lines. Some video cards (notably those based on S3 chips) use IO addresses in the form of 0x*2e8, and since many cheap serial cards do not fully decode the 16-bit IO address space, they clash with these cards making the COM4 port practically unavailable. Each serial port is required to have a unique IRQ (unless you are using one of the multiport cards where shared interrupts are supported), so the default IRQs for COM3 and COM4 cannot be used. # Parallel port device ppc0 at isa? irq 7 This is the ISA-bus parallel port interface. device ppbus # Parallel port bus (required) Provides support for the parallel port bus. device lpt # Printer Support for parallel port printers. All three of the above are required to enable parallel printer support. device plip # TCP/IP over parallel This is the driver for the parallel network interface. device ppi # Parallel port interface device The general-purpose I/O (geek port) + IEEE1284 I/O. #device vpo # Requires scbus and da zip drive This is for an Iomega Zip drive. It requires scbus and da support. Best performance is achieved with ports in EPP 1.9 mode. # PCI Ethernet NICs. device de # DEC/Intel DC21x4x (Tulip) device fxp # Intel EtherExpress PRO/100B (82557, 82558) device tx # SMC 9432TX (83c170 EPIC) device vx # 3Com 3c590, 3c595 (Vortex) device wx # Intel Gigabit Ethernet Card (Wiseman) Various PCI network card drivers. Comment out or remove any of these not present in your system. # PCI Ethernet NICs that use the common MII bus controller code. device miibus # MII bus support MII bus support is required for some PCI 10/100 ethernet NICs, namely those which use MII-compliant transceivers or implement transceiver control interfaces that operate like an MII. Adding device miibus to the kernel config pulls in support for the generic miibus API and all of the PHY drivers, including a generic one for PHYs that are not specifically handled by an individual driver device dc # DEC/Intel 21143 and various workalikes device rl # RealTek 8129/8139 device sf # Adaptec AIC-6915 (Starfire) device sis # Silicon Integrated Systems SiS 900/SiS 7016 device ste # Sundance ST201 (D-Link DFE-550TX) device tl # Texas Instruments ThunderLAN device vr # VIA Rhine, Rhine II device wb # Winbond W89C840F device xl # 3Com 3c90x (Boomerang, Cyclone) Drivers that use the MII bus controller code. # ISA Ethernet NICs. device ed0 at isa? port 0x280 irq 10 iomem 0xd8000 device ex device ep # WaveLAN/IEEE 802.11 wireless NICs. Note: the WaveLAN/IEEE really # exists only as a PCMCIA device, so there is no ISA attachment needed # and resources will always be dynamically assigned by the pccard code. device wi # Aironet 4500/4800 802.11 wireless NICs. Note: the declaration below will # work for PCMCIA and PCI cards, as well as ISA cards set to ISA PnP # mode (the factory default). If you set the switches on your ISA # card for a manually chosen I/O address and IRQ, you must specify # those parameters here. device an # The probe order of these is presently determined by i386/isa/isa_compat.c. device ie0 at isa? port 0x300 irq 10 iomem 0xd0000 device fe0 at isa? port 0x300 device le0 at isa? port 0x300 irq 5 iomem 0xd0000 device lnc0 at isa? port 0x280 irq 10 drq 0 device cs0 at isa? port 0x300 device sn0 at isa? port 0x300 irq 10 # requires PCCARD (PCMCIA) support to be activated #device xe0 at isa? ISA ethernet drivers. See /usr/src/sys/i386/conf/LINT for which cards are supported by which driver. # Pseudo devices - the number indicates how many units to allocated. pseudo-device loop # Network loopback This is the generic loopback device for TCP/IP. If you telnet or FTP to localhost (a.k.a., 127.0.0.1) it will come back at you through this pseudo-device. This is mandatory. pseudo-device ether # Ethernet support ether is only needed if you have an Ethernet card. It includes generic Ethernet protocol code. pseudo-device sl 1 # Kernel SLIP sl is for SLIP support. This has been almost entirely supplanted by PPP, which is easier to set up, better suited for modem-to-modem connection, and more powerful. The number after sl specifies how many simultaneous SLIP sessions to support. pseudo-device ppp 1 # Kernel PPP This is for kernel PPP support for dial-up connections. There is also a version of PPP implemented as a userland application that uses tun and offers more flexibility and features such as demand dialing. The number after ppp specifies how many simultaneous PPP connections to support. pseudo-device tun # Packet tunnel. This is used by the userland PPP software. The number after tun specifies the number of simultaneous PPP sessions to support. See the PPP section of this book for more information. pseudo-device pty # Pseudo-ttys (telnet etc) This is a pseudo-terminal or simulated login port. It is used by incoming telnet and rlogin sessions, xterm, and some other applications such as emacs. The number indicates the number of ptys to create. If you need more than the default of 16 simultaneous xterm windows and/or remote logins, be sure to increase this number accordingly, up to a maximum of 256. pseudo-device md # Memory disks Memory disk pseudo-devices. pseudo-device gif 4 # IPv6 and IPv4 tunneling This implements IPv6 over IPv4 tunneling, IPv4 over IPv6 tunneling, IPv4 over IPv4 tunneling, and IPv6 over IPv6 tunneling. pseudo-device faith 1 # IPv6-to-IPv4 relaying (translation) This pseudo-device captures packets that are sent to it and diverts them to the IPv4/IPv6 translation daemon. # The `bpf' pseudo-device enables the Berkeley Packet Filter. # Be aware of the administrative consequences of enabling this! pseudo-device bpf # Berkeley packet filter This is the Berkeley Packet Filter. This pseudo-device allows network interfaces to be placed in promiscuous mode, capturing every packet on a broadcast network (e.g., an ethernet). These packets can be captured to disk and or examined with the &man.tcpdump.1; program. # USB support #device uhci # UHCI PCI->USB interface #device ohci # OHCI PCI->USB interface #device usb # USB Bus (required) #device ugen # Generic #device uhid # Human Interface Devices #device ukbd # Keyboard #device ulpt # Printer #device umass # Disks/Mass storage - Requires scbus and da #device ums # Mouse # USB Ethernet, requires mii #device aue # ADMtek USB ethernet #device cue # CATC USB ethernet #device kue # Kawasaki LSI USB ethernet Support for various USB devices. For more information and additional devices supported by FreeBSD, see /usr/src/sys/i386/conf/LINT. Making Device Nodes device nodes MAKEDEV Almost every device in the kernel has a corresponding node entry in the /dev directory. These nodes look like regular files, but are actually special entries into the kernel which programs use to access the device. The shell script /dev/MAKEDEV, which is executed when you first install the operating system, creates nearly all of the device nodes supported. However, it does not create all of them, so when you add support for a new device, it pays to make sure that the appropriate entries are in this directory, and if not, add them. Here is a simple example: Suppose you add the IDE CD-ROM support to the kernel. The line to add is: device acd0 This means that you should look for some entries that start with acd0 in the /dev directory, possibly followed by a letter, such as c, or preceded by the letter r, which means a raw device. It turns out that those files are not there, so you must change to the /dev directory and type: MAKEDEV &prompt.root; sh MAKEDEV acd0 When this script finishes, you will find that there are now acd0c and racd0c entries in /dev so you know that it executed correctly. For sound cards, the following command creates the appropriate entries: &prompt.root; sh MAKEDEV snd0 When creating device nodes for devices such as sound cards, if other people have access to your machine, it may be desirable to protect the devices from outside access by adding them to the /etc/fbtab file. See &man.fbtab.5; for more information. Follow this simple procedure for any other non-GENERIC devices which do not have entries. All SCSI controllers use the same set of /dev entries, so you do not need to create these. Also, network cards and SLIP/PPP pseudo-devices do not have entries in /dev at all, so you do not have to worry about these either. If Something Goes Wrong There are four categories of trouble that can occur when building a custom kernel. They are: config fails If the config command fails when you give it your kernel description, you have probably made a simple error somewhere. Fortunately, config will print the line number that it had trouble with, so you can quickly skip to it with vi. For example, if you see: config: line 17: syntax error You can skip to the problem in vi by typing 17G in command mode. Make sure the keyword is typed correctly, by comparing it to the GENERIC kernel or another reference. make fails If the make command fails, it usually signals an error in your kernel description, but not severe enough for config to catch it. Again, look over your configuration, and if you still cannot resolve the problem, send mail to the &a.questions; with your kernel configuration, and it should be diagnosed very quickly. The kernel will not boot If your new kernel does not boot, or fails to recognize your devices, do not panic! Fortunately, BSD has an excellent mechanism for recovering from incompatible kernels. Simply choose the kernel you want to boot from at the FreeBSD boot loader (i.e., boot kernel.old). When reconfiguring a kernel, it is always a good idea to keep a kernel that is known to work on hand. After booting with a good kernel you can check over your configuration file and try to build it again. One helpful resource is the /var/log/messages file which records, among other things, all of the kernel messages from every successful boot. Also, the &man.dmesg.8; command will print the kernel messages from the current boot. If you are having trouble building a kernel, make sure to keep a GENERIC, or some other kernel that is known to work on hand as a different name that will not get erased on the next build. You cannot rely on kernel.old because when installing a new kernel, kernel.old is overwritten with the last installed kernel which may be non-functional. Also, as soon as possible, move the working kernel to the proper kernel location or commands such as &man.ps.1; will not work properly. The proper command to unlock the kernel file that make installs (in order to move another kernel back permanently) is: &prompt.root; chflags noschg /kernel And, if you want to lock your new kernel into place, or any file for that matter, so that it cannot be moved or tampered with: &prompt.root; chflags schg /kernel The kernel works, but ps does not work any more! If you have installed a different version of the kernel from the one that the system utilities have been built with, for example, a 4.X kernel on a 3.X system, many system-status commands like &man.ps.1; and &man.vmstat.8; will not work any more. You must recompile the libkvm library as well as these utilities. This is one reason it is not normally a good idea to use a different version of the kernel from the rest of the operating system.