tcpdump and local packet capturing

[Marc Bohnert]

How do I capture the IP packets from client to server when both ends exist on the same server. The packets do not go through the interface but are routed internally.

HPUX 11

Thanks

[The Real MD]

try using localhost or 127.0.0.1 as the host your listening to.

tcpdump host localhost

Regards

Martin.

[Mika Sipila]

Currently it's not possible. tcpdump (or actually libpcap) won't listen to lo0 because it can't find /dev/lo0. My system at least is missing the loopback interface device file.

The correct syntax would be tcpdump -i lo0
If -i is not specified, tcpdump will use the lowest network interface found (usually lan0).

Plaese speak out if you know some way to tweak this.