Subject: lo interface 2.2 to 2.3 migration issue
From: Corin Langosch <corinl@gmx.de>
Date: Sun, 22 Feb 2009 11:43:03 +1300

Hi again!

I migrated from vserver 2.2.0.6 (kernel 2.6.22) to 0.30.216-pre2772
(kernel 2.6.26) and have another network issue. I have a daemon running
in a guest and binding to 127.0.0.1:8002 (netstat -lnp shows correct
output). Now a client running in the same guest now wants to connect to
this daemon. The connection fails. Even testing the stuff with telnet
fails.

I double checked the host, no firewall (iptables) rules are preventing
any packets. I tried to capture the traffic with "tcpdump -n dst
127.0.0.1" but this shows no packets (I guess they don't leave the guest
and so the host can't trace them). Tcpdump in the guest is not working
due to security restrictions, so I can't check what's exactly happening
there.

As it used to work without any problems before I think something changed
between the used versions concerning the lo interface. How to get it
working again? Btw, normales interfaces are working fine.

Thanks,
Corin