sounds like a driver issue to me here's what i found on the ubuntu forums:
auto eth0 error
I recently installed ubuntu 8.10 on my dell 1520 laptop however my ethernet port will try to connect for a few seconds then pop up with a message saying "The network connection has been disconnected". Does anyone know what is causing this, I have had 7.04 on the same computer before and it worked flawlessly.
edit: I set up a manual wired connection with the proper Netmask, IP, Gateway and DNS Servers. Also checked multiple cables problem still prosistes, other computers running win xp and lepord 10.5 work fine with the network. I dont know if it will help but I'm useing a bilkin G router model FSD7230-4
edit2: I ended up downloading the dell version of ubuntu 7.04 now it will connect to the network buy still can't get online, once again I dont know why, though this is father then i got before
the link to dells version of ubuntu is here
http://linux.dell.com/wiki/index.php/Ubuntu_7.04
edit3: SOLVED wow I am dumb didnt even think about adding the mac address to my routers filter settings until just now, it works now.
Last edited by Baconfatty; December 10th, 2008 at 05:48 AM..
edit: does this still happen for you? I think you have to rename your connection or create a new one. The auto connections are somewhat read-only - until you renamed them.