Big warning about network configuration option in Ubuntu on a VPS
See the button that says "Network Configuration" under "Server Config"?
"Network Configuration The network configuration option is only available for Debian and Ubuntu Servers. Do not enable this option if your network interface is not eth0."
I have a ubuntu 11.10 server and the interface is eth0. It's a Xen-based VPS on a vlan.
I pushed the button.
There followed 6 hours of hell while I worked overnight trying to get to my now-dead server. Couldn't even connect to do an emergency rollback or reboot. At 8am, a very helpful and friendly senior admin spent nearly an hour of his time (which he didn't have to do) recovering the system.
We managed to get it back to being able to connect on the 3 IP addresses we had before, but he said the numbers were "all over the place". It had set things like the gateway to 192.168.0.1, and when he tried to to ifup, it said something like the interface couldn't be linked. We couldn't add any more.
In the end, we just took the whole /www dir, switched to a new server and I re-installed everything (was going to do it anyway, just not quite then!)
Incredibly annoyingly, I made a notepad full of notes about what he said and what it had changed to, but everything in /etc/interfaces was wrong, from the subnet mask to the gateway to the broadcast - all totally wrong for the VPS!
So, it MIGHT be something to do with it being a VPS, but unless you really REALLY need to push that button, or have a backup plan, just don't!