I have had a working setup for 3 weeks which suddenly stopped working this morning. I can't identify what changed. I have two network interfaces on my main (Ubuntu 10.10) PC; eth0 is an ethernet card connected to the Internet and eth1 is a USB network interface which I connect to my laptop. I bridge eth0 and eth1 so all my laptop's internet traffic goes through my main PC (university network).
Last night this worked perfectly. This morning eth1 does not appear when I do 'ifconfig'. Also in the gnome network manager the usb adapter (eth1) is greyed out. When I run 'sudo ifconfig eth1 up' I get 'SIOCSIFFLAGS: Cannot assign requested address'. When I run 'sudo ifconfig eth1 18.104.22.168' I get the same.
I also noticed that when I run 'sudo lspci' there is no mention of an ethernet interface at all (both connections I'm using are ethernet and eth0 works fine).
Could anyone suggest how I should go about troubleshooting this?
Edit: I can also ping 192.168.0.1 (eth1) and I get a reply