Adding the Internal Windows DNS server to the TCP properties did the trick. My Acitve Directory Forrest and my Active Directory Domain are the same (xyz.com). I still have a small issue. I still need to enable SMB/CIFS to be able to see the shared files on our Domain. I was able to see these files without joining the domain in the first place. Do I need to have this SMB/CIFS enabled? I would like to use my MacBook Pro (Tiger OSX 10.4.10) to login to the domain just as I would (or in similar fashion to) a Windows box. When SMB is enabled, I still need to enter my username and password every time to view folders on our company file server. I want to be able to use the Domain Controller user attributes assigned to me to allow access instead.