Networking :: Pinging Localhost Comes From Source Of Eth0

I was doing some one-handed-one-fingered typing while talking on the phone. Due to lack of paying attention, I executed the following command: ifconfig eth0 1300 (was meant to be ifconfig eth0 mtu 1300) this of course killed the connection, so I got the box rebooted. This box functions as an openswan/firewall server. everything came up okay, end users are reporting no problems with the vpn or the firewall function. However, one service is failing because the route to localhost seems to be originating from eth0. when I `ping localhost`, the traffic dump shows the ping packet originating from the external address. On all my other boxes, when I ping localhost, the traffic originates from localhost. The reply to my ping behaves normally.

here is a dump of my pinging localhost: fw-ps:~/scripts# tcpdump -n -i lo listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes 10:00:01.885033 IP 194.246.23.22 > 127.0.0.1: ICMP echo request, id 6893, seq 12, length 64 10:00:01.885068 IP 127.0.0.1 > 127.0.0.1: ICMP echo reply, id 6893, seq 12, length 64

I considered trying to manually add some routes, but since the reply is working, I am not sure that is the problem. I also considered trying to change the default interface, but I don't want external traffic originating from the loopback.