Index: head/usr.sbin/arp/arp.4 =================================================================== --- head/usr.sbin/arp/arp.4 +++ head/usr.sbin/arp/arp.4 @@ -28,7 +28,7 @@ .\" @(#)arp4.4 6.5 (Berkeley) 4/18/94 .\" $FreeBSD$ .\" -.Dd October 3, 2016 +.Dd October 7, 2016 .Dt ARP 4 .Os .Sh NAME @@ -121,67 +121,65 @@ MIB. .Bl -tag -width "log_arp_permanent_modify" .It Va allow_multicast -Should the kernel install ARP entries with multicast bit set in -the hardware address. -Installing such entries is RFC 1812 violation, but some prorietary -load balancing techniques require routers on network to do so. +Install ARP entries with the multicast bit set in the hardware address. +Installing such entries is an RFC 1812 violation, but some proprietary load +balancing techniques require routers to do so. Turned off by default. .It Va garp_rexmit_count -Should the kernel retransmit gratuitous ARP (GARP) packets when an IPv4 address -is added to an interface. +Retransmit gratuitous ARP (GARP) packets when an IPv4 address is added to an +interface. A GARP is always transmitted when an IPv4 address is added to an interface. -A non-zero value of this sysctl will cause the GARP packet to be retransmitted -the stated number of times. +A non-zero value causes the GARP packet to be retransmitted the stated number +of times. The interval between retransmissions is doubled each time, so the retransmission intervals are: {1, 2, 4, 8, 16, ...} (seconds). The default value of zero means only the initial GARP is sent; no additional GARP packets are retransmitted. The maximum value is sixteen. .Pp -Although a single GARP packet (the default behavior) is usually sufficient, in -some circumstances, such as when a shared address is passed between cluster -nodes, this single GARP may be dropped or lost. -This can lead to neighbors on the network link working with a stale ARP cache -and sending packets destined for that address to the node that previously owned -the address, which may not respond. +The default behavior of a single GARP packet is usually sufficient. +However, a single GARP might be dropped or lost in some circumstances. +This is particularly harmful when a shared address is passed between cluster +nodes. +Neighbors on the network link might then work with a stale ARP cache and send +packets destined for that address to the node that previously owned the +address, which might not respond. .It Va log_arp_movements -Should the kernel log movements of IP addresses from one hardware -address to an other. +Log movements of IP addresses from one hardware address to another. See .Sx DIAGNOSTICS below. Turned on by default. .It Va log_arp_permanent_modify -Should the kernel log attempts of remote host on network to modify a -permanent ARP entry. +Log attempts by a remote host to modify a permanent ARP entry. See .Sx DIAGNOSTICS below. Turned on by default. .It Va log_arp_wrong_iface -Should the kernel log attempts to insert an ARP entry on an interface -when the IP network the address belongs to is connected to an other -interface. +Log attempts to insert an ARP entry on an interface when the IP network to +which the address belongs is connected to another interface. See .Sx DIAGNOSTICS below. Turned on by default. .It Va max_log_per_second -Limit number of remotely triggered logging events to a configured value -per second. +Limit the number of remotely triggered logging events to a configured value per +second. Default is 1 log message per second. .It Va max_age How long an ARP entry is held in the cache until it needs to be refreshed. Default is 1200 seconds. .It Va maxhold -How many packets hold in the per-entry output queue while the entry +How many packets to hold in the per-entry output queue while the entry is being resolved. Default is one packet. .It Va maxtries -Number of retransmits before host is considered down and error is returned. +Number of retransmits before a host is considered down and an error is +returned. Default is 5 tries. .It Va proxyall -Enables ARP proxying for all hosts on net. +Enables ARP proxying. Turned off by default. .It Va wait Lifetime of an incomplete ARP entry.