It sounds like you have the full graphic install of Ubuntu (Gnome, I'm assuming, rather than Kubuntu).
You'll want to shut a lot of things off - in fact, if you're using this machine remotely, for the most part, you might want to just remove gnome completely, and use one of the lightweight X managers (if any at all).
As for the network settings - I don't use the network-manager tool. I remove it completely from servers, then do everything by hand - since I have no need/intention of changing the IP addresses once installed. (meaning I modify the interfaces file)