Restarting the network

[R Kimber]

After my broadband goes down and is then restored, my networking  never
restores automatically, and the command that Googling leads me to understand
should restore it never works:
sudo /etc/init.d/networking restart
I've also tried 
ifup eth0
and
sudo /etc/init.d/network-manager restart

In each case I get errors about eth0 being unknown.

The logs say:-
Mar  3 15:00:40 infinity NetworkManager: <info>  (eth0): DHCP transaction
took too long, stopping it.
Mar  3 15:00:40 infinity NetworkManager: <info>  (eth0): canceled DHCP
transaction, dhcp client pid 1487
Mar  3 15:00:40 infinity NetworkManager: <info>  Activation (eth0) Stage 4
of 5 (IP4 Configure Timeout) scheduled...
Mar  3 15:00:40 infinity NetworkManager: <info>  Activation (eth0) Stage 4
of 5 (IP4 Configure Timeout) started... 
Mar  3 15:00:40 infinity NetworkManager: <info> (eth0): device state
change: 7 -> 9 (reason 5)
Mar 3 15:00:40 infinity NetworkManager: <info> Marking connection 'Auto
eth0' invalid.
Mar  3 15:00:40 infinity NetworkManager: <info>  Activation (eth0) failed.
Mar  3 15:00:40 infinity NetworkManager: <info>  Activation (eth0) Stage 4
of 5
 (IP4 Configure Timeout) complete.
Mar  3 15:00:40 infinity NetworkManager: <info>  (eth0): device state
change: 9 -> 3 (reason 0)
Mar 3 15:00:40 infinity NetworkManager: <info> (eth0): deactivating device
(reason: 0).

The only thing that works is a reboot.  Am I using the wrong commands?  Or
is there a tweak that will overcome the problem?

- Richard
-- 
Richard Kimber
Political Science Resources
http://www.PoliticsResources.net/