I needed to find out which ports were being used by Team Explorer to communicate with the TFS server.
With Team Explorer 2008 and TFS 2008, I found that the following ports were being used
The first two were being used by devenv.exe (Visual Studio). The last one (microsoft-ds) was being used by the system (not sure why this port is being used – but I suspect it might be TFS shell integration power-toys that are using it, as the communications is being initiated by [system]).
So, if you need to open a firewall between your client machines and the TFS server, I would start with the above 3 ports associated with your TFS server address.
Other useful information:
Read the topic “Ports required during installation” in the TFSInstall Guide.