Interference

If you've been following along you'll know that we recently moved our infrastructure over to our Cisco switches/routers.
One of the things we've been doing is implementing our management network - hooking into the APC UPS and getting all the management software to remotely administer the machines if necessary. So that means each machine has 3 network connections: a primary, a secondary for failover and the management network. Well, the management network was set up but not completely configured. The interfaces are trying to DHCP and we don't have a DHCP server on that management network. So the interfaces - a PPP connection - ends up with the default "I can't get an address" address.
This was causing headaches. For some reason, our DNS server decided that this "no address" address was its primary connection and was returning it in response to queries for it IP address. Since this is also our ADS server, you can imagine the problems on the network just from that. Then to add to the problem our mail server did the same thing, putting both of them on the same address and wreaking complete havoc throughout our network.
I shut down the management interfaces and rebooted (cause rebooting Windows is the best fix for problems) and voila! All is well again.