About an hour later, I remoted into the server to fix some longstanding configuration issues and do an initial reboot after clearing the server's logs (to check for any new problems). Again, this went off fine.
Then just now I was trying to solve a problem with my hypervisor, so I disabled the firewall and... the connection died. Yes, disabling the firewall resulted in a loss of all connectivity. I called my datacentre and they're sending a guy out to take a look at my rack, I hope to have it back up online shortly.
Yes, this is a huge embrassement.
UPDATE: I've got the servers backonline after getting the datacentre staff to take a quick look and give the whole she-bang a powercycle. Crude, but effective.
I wish I could afford a proper KVM-over-IP solution, but the stuff I need starts at £360.
Edited by W3bbo, 22 September 2009 - 06:18 PM.