diff --git a/sbin/ipf/ipnat/ipnat.5 b/sbin/ipf/ipnat/ipnat.5
--- a/sbin/ipf/ipnat/ipnat.5
+++ b/sbin/ipf/ipnat/ipnat.5
@@ -332,7 +332,7 @@
 rdr le0 0/0 -> 192.168.1.0
 .fi
 .PP
-Will not spread packets across all 256 IP addresses in that class C network.
+Will not spread packets across all 256 IP addresses in that /24 subnet.
 If you were to try a rule like this:
 .nf
 
diff --git a/sys/netinet/libalias/libalias.3 b/sys/netinet/libalias/libalias.3
--- a/sys/netinet/libalias/libalias.3
+++ b/sys/netinet/libalias/libalias.3
@@ -200,11 +200,11 @@
 .It Dv PKT_ALIAS_UNREGISTERED_ONLY
 If this mode bit is set, traffic on the local network which does not
 originate from unregistered address spaces will be ignored.
-Standard Class A, B and C unregistered addresses are:
+The standard private IP address ranges are:
 .Pp
-10.0.0.0     ->  10.255.255.255   (Class A subnet)
-172.16.0.0   ->  172.31.255.255   (Class B subnets)
-192.168.0.0  ->  192.168.255.255  (Class C subnets)
+10.0.0.0           ->        10.255.255.255   (/8)
+172.16.0.0         ->        172.31.255.255   (/16)
+192.168.0.0        ->        192.168.255.255  (/24)
 .Pp
 This option is useful in the case that the packet aliasing host has both
 registered and unregistered subnets on different interfaces.
diff --git a/usr.sbin/ppp/ppp.8 b/usr.sbin/ppp/ppp.8
--- a/usr.sbin/ppp/ppp.8
+++ b/usr.sbin/ppp/ppp.8
@@ -2202,8 +2202,8 @@
 unobtrusive and unspecific IP number as your address.
 10.0.0.1/0 would be appropriate.
 The bit after the / specifies how many bits of the
-address you consider to be important, so if you wanted to insist on
-something in the class C network 1.2.3.0, you could specify 1.2.3.1/24.
+address you consider to be important, so if you wanted to specify an
+address within the 1.2.3.0/24 subnet, you could specify 1.2.3.1/24.
 .It
 If you find that your ISP accepts the first IP number that you suggest,
 specify third and forth arguments of
@@ -3186,7 +3186,7 @@
 Default: Disabled.
 Enabling this will tell
 .Nm
-to add proxy arp entries for every IP address in all class C or
+to add proxy arp entries for every IP address in all /24 subnets or
 smaller subnets routed via the tun interface.
 .Pp
 Proxy arp entries are only made for sticky routes that are added