DNS and Internet

I have a W2K Server, SP2, running DNS and Active Directory. All of my users are authenticating successfully and DNS is set up correctly. My confusion is that when I access the internet from my W2K server i cannot access the internet. I have the primary DNS servers IP Address to point to itself. I also have the Secondary DNS server specified as an internet DNS. But when i replace the primary’s DNS address with a internet DNS i can browse the internet without a problem. Any help please

Thanks
Len