The consensus is that FreeBSD will forward packets from the private address
group as defined in RFC 1597.
I built a test network to prove the concept and it appears that FreeBSD
does
not forward private IP packets. The info describing the network is as
follows:
ifconfig -a
eth0: flags=41<UP,RUNNING> mtu 1500
inet 211.1.1.89 netmask 0xffffffff
de0: flags=8863<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 198.136.226.1 netmask 0xffffff00 broadcast 198.136.226.255
ether 00:00:f8:01:51:b1
de1: flags=8863<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 192.168.1.1 netmask 0xffffff00 broadcast 192.168.1.255
ether 00:00:f8:01:51:bd
lo0: flags=8009<UP,LOOPBACK,MULTICAST> mtu 16384
inet 127.0.0.1 netmask 0xff000000
sl0: flags=c010<POINTOPOINT,LINK2,MULTICAST> mtu 552
etha100: flags=51<UP,POINTOPOINT,RUNNING> mtu 1500
inet 206.137.132.18 --> 206.137.132.17 netmask 0xfffffffc
etha101: flags=51<UP,POINTOPOINT,RUNNING> mtu 1500
inet 207.76.242.1 --> 207.76.242.2 netmask 0xfffffffc
netstat -rn
Routing tables
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 206.137.132.17 UGSc 8 27856 etha100
127.0.0.1 127.0.0.1 UH 0 5 lo0
192.168.1 link#3 UC 0 0
192.168.1.1 0:0:f8:1:51:bd UHLW 0 22 lo0
192.168.1.2 aa:0:4:0:6:4 UHLW 0 5 de1 891
192.168.1.5 0:0:f8:0:2:e4 UHLW 0 22 de1 717
198.136.226 link#2 UC 1 0
198.136.226.1 0:0:f8:1:51:b1 UHLW 1 313 lo0
198.136.226.5 0:0:f8:1:4b:f7 UHLW 0 118 de0 1132
198.136.226.7 0:0:f8:1:51:7d UHLW 1 1738 de0 1094
198.136.226.10 0:0:c0:33:8c:d6 UHLW 1 40 de0 538
206.67.12 206.137.132.17 UGSc 1 5 etha100
206.137.132.17 206.137.132.18 UH 11 0 etha100
207.76.242.2 207.76.242.1 UH 2 66 etha101
211.1.1.89 211.1.1.89 Uc 0 0 eth0
>From host address on the 192.168.1.0 net I cannot ping or traceroute past
192.168.1.1. From the
BSD box (192.168.1.1 and 198.136.226.1) I can reach everybody. From
207.76.242.1 I can reach
all hosts in the 198.136.226.0 network (and the rest of the internet for
that matter), however, the
192.168.1.0 net is totally unreachable. From hosts on the 198.136.226.0
network I can reach
everywhere except the 192.168.1.0 net. IPFW kernel options are enabled but
no firewall chain entries
exist. IP forwarding is enabled. FreeBSD version 2.1.0.
It appears that FreeBSD does not forward private IP addresses or am I
missing something?
-- Chris Peltier