Network interface mystery

I did something yesterday I hadn’t done in a while, I rebooted my Gentoo Linux box. I use it for samba shares/backups, DNS & DHCP (using dnsmasq), and it also does a good job of protein folding in its spare time(Foldingathome). I have also been extremely good about keeping the system up to date using the portage package manager. After the reboot though, my poor little box was isolated from the network and it made no sense. The routing was correct, the link lights were lit on my two network cards. I have two because one is used to talk to the rest of the network through my router and the other plugs into my Vonage IAD (Integrated Access Device for those of you not into telecom voip lingo) for maintenance of that box, if needed. So everything looks correct, and I am driving myself somewhat insane resetting the router, re-verifying everything but still no love … I’ve been using this static IP setup since sometime in 2004 and if this box isn’t talking to the network everything goes to a bad place since no dns & dhcp are available. Looking online I found little (once I got a computer talking to the internet by bypassing things). So here is the punchline … apparently the latest and greatest version of udev initializes my ethernet cards in a different order, so my former eth0 is now eth1 and vice versa. After changing some config files around to use the eth0 interface instead of eth1 all is now well (after the fact though, I do realize I could have just swapped the cables in the network cards to achieve the same effect).

If you have this problem sometime in the future, I hope this helps.