I don't expect anything strange from 'ifconfig' but just tell me the name of your device. Is it 'eth0'? Most likely it is if it's wired so try this:
ifconfig eth0 up
Is this your home network? Do you know the network address? (e.g., 192.168.1.0)
I believe Ubuntu uses 'dhcpcd'. If not, substitute that for 'dhclient'. Post back with your results.