I was recently helping a friend who was having trouble getting online with her Mac laptop.  After over an hour of talking to Apple they told her that her computer was self assigning the IP address, but did not tell her how to fix it. 

A little bit of forum scouring provided me with more than a few people who are having the same issues and a few ideas of how to fix this issue.  The idea that seems to have fixed the problem was resetting the PRAM.  Parameter RAM, or PRAM, is a small amount of RAM that stores the basic setup information about the computer.  This includes settings for the mouse, keyboard, startup, etc.  Warning, you may lose some of your customized settings.  However, you can use the Control Panels to restore them.  Here are the steps to reset your PRAM:  [more]

  1. Shut down the computer.
  2. Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
  3. Turn on the computer.
  4. Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
  5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.
  6. Release the keys.