I’m back online. Changing network configuration on remote machines is painful.
I’m not going to detail what happened, but I’ll say that it is related to a debian 2.0 time period way of doing things. I didn’t even know that I still had that /etc/init.d/network file in place and linked to execute on boot. Oops. No wonder that /etc/init.d/networking file wasn’t making things work properly. br0 was set to start on boot, but it used eth0 which was being configured by the networks script. The inconsistent state was making things barf. And it made me cry.
Calling my Dad and walking him through linux server configuration isn’t the easiest, but what did help was logging him into MSN and using the Remote Assistance piece.
… in the end, it turns out that… the default gateway on the linux server wasn’t set. ;[