I'm having a problem where our Windows Server 2003 domain controller assigns my Windows 7 computer one IP address (x.x.x.75) via DHCP, but reports another (x.x.x.84) via DNS. This causes some interesting behavior on the network. If I change my adapter settings to get IP and DNS addresses from DHCP, I can access the internet, but no one on our network can access my computer. If I change my IP manually to what DNS says it is, I lose my internet access, but everyone can get to my computer again.

I know that we have some old, invalid reverse DNS pointers hanging around (a reverse lookup on an IP address often gives more than one result, usually not including the one that is correct), so that could be contributing, but my problem is recent, and the invalid reverse pointers have been around a long time.

What's going on, and how do I fix it?