Try, http://www.netfilter.org/unreliable-guides/NAT-HOWTO/NAT-HOWTO.linuxdoc-4.html#ss4.1 masquerading works well for me 2.4.20 kernel, don't forget : #echo 1 > /proc/sys/net/ipv4/ip_forward or your gateway box will not forward packets from the internal network. -Mel