Well, to troubleshoot you are going to need to learn to set up the interface manually using the ifconfig and the route command. When DHCP does not work properly, this is how to trouble shoot the problem in a systematic way.

You can easily do this by read the man pages:

Alternatively, you could purchase a good book on TCP/IP Network Administration, like this classic O'Reilly book:

http://www.amazon.com/exec/obidos/tg...books&n=507846