aliasing an interface: ifconfig IF:XX new_settings up
as in: (eth0 already configured) ifconfig eth0:0 192.168.2.1 network 192.168.2.255 broadcast 255.255.255.0 up this will have eth0 as the usual interface, and eth0:0 pointing to the same hardware nic, but with different network settings. Have fun. PS: your configuration, with one of the computers on a single LAN acting as a gateway between two IP networks, works perfectly here, with only one nic per computer (afterall, this is what aliasing has been invented for) PS2: another good solution would be to user a RIP daemon.
