First, check that your
dhclient.conf file is present. It should look somewhat like this:
Code:
$ cat /etc/dhcp3/dhclient.conf | grep -v ^#
option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
send host-name "<hostname>";
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, domain-search, host-name,
netbios-name-servers, netbios-scope, interface-mtu,
rfc3442-classless-static-routes, ntp-servers;
If that looks correct, see if
sudo dhclient wlan0 fixes the problem. (Note that "wlan0" should be replaced by your actual connection name. "wlan0" is typical for a wireless connection, but other name are often used.)
If that works, see if you can figure out why
dhclient is not being started correctly when you boot.