Поднял на машине freeBSD 8.2, перекомпилил ядро с поддержкой ipfw, поднял isc - dhcpd и мучаюсь с натом. в системе существует три интерфейса, вывод ifconfig
em0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=219b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_MAGIC>
ether 00:15:17:6e:e9:bc
media: Ethernet autoselect (100baseTX <full-duplex>)
status: active
re0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=389b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_UCAST,WOL_MCAST,WOL_MAGIC>
ether d8:5d:4c:80:ce:3e
inet 192.168.1.173 netmask 0xffffff00 broadcast 192.168.1.255
media: Ethernet autoselect (100baseTX <full-duplex>)
status: active
re1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=389b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_UCAST,WOL_MCAST,WOL_MAGIC>
ether d8:5d:4c:80:de:8b
inet 192.168.0.254 netmask 0xffffff00 broadcast 192.168.0.255
media: Ethernet autoselect (100baseTX <full-duplex>)
status: active
ipfw0: flags=8801<UP,SIMPLEX,MULTICAST> metric 0 mtu 65536
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
options=3<RXCSUM,TXCSUM>
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x5
inet6 ::1 prefixlen 128
inet 127.0.0.1 netmask 0xff000000
nd6 options=3<PERFORMNUD,ACCEPT_RTADV>
add 10 allow ip from any to any via re0
nat 1 config log if re1 reset same_ports