Hello, Given the network map below, I am able to ping any ip on all networks from the linux box. However, from the cisco router, I cannot ping past eth1 on the linux box. The reverse is also true; I cannot ping past eth0 from a host on LAN. proxy-arp is enabled on the linux box and the route to a.b.c.0/24 is added to the cisco router. I haven't a clue why either way, I can only get to the far side of the linux box but no further. On second thought, maybe this is not an application for proxy-arp. Your thoughts are appreciated. T1 to ISP | | /30 net | +----------------+ | cisco router | +----------------+ | FastEthernet0/0 | a.b.c.1/28 | (possible switch/hub here in future) (ip range = a.b.c.1-15) | | a.b.c.2/28 | eth0 +----------------+ | | | eth1 |---a.b.c.16/24-public-net-----> LAN | | (ip range = a.b.c.16-255) | linux box | | eth2 |---192.168.1.0/24-- * | | * (not revelant to discussion) +----------------+ David Koski david@KosmosIsland.com