Timeout in a connection to a DHCP server

For setting DHCP client timeout from CLI read this.

You can also just configure DHCP clients configuration file. You can find the guide for that here. On my 12.04 the dhclient.conf file that you need to edit is uder /etc/dhcp/

So from CLI open the file with this:

sudo nano /etc/dhcp/dhclient.conf

Scroll to the line where it says "#timeout 60;" and remove the "#" sign. Change the number to set the timeout in seconds. Press Ctrl + X to exit the editor and save the changes.

If you can't wait until the next reboot then to force Ubuntu to reacquire a new IP address from the DHCP server run:

sudo dhclient -r

You can try to set:

timeout 10;
backoff-cutoff 0;
initial-interval 0;
retry 15;

In /etc/dhcp/dhclient.conf.

See dhclient.conf manpage (man dhclient.conf) for reference.