Today has been long. I’ve been trying to figure out why on earth my Remote Debugger wouldn’t run. I had the Remote Debugging Monitor set up correctly on both machines, but I kept getting an error message about DCOM:

“Unable to start debugging on the web server. The Visual Studio Remote Debugger on the target computer cannot connect back to this computer. A firewall may be preventing communication via DCOM to the local computer.”

Come to find out, not only could VS Remote Debugger not access my local computer, I couldn’t even ping myself from the server.

I spent most of the day playing with firewall and IPSec policies, until I stumbled on THIS forum post.

Come to find out, Windows Live OneCare has its own firewall configuration settings. Once you track this down, John Robbins provides all of the basic exceptions needed in the firewall:

Microsoft Visual Studio Remote Debugger – UDP 137
Microsoft Visual Studio Remote Debugger – UDP 138
Microsoft Visual Studio Remote Debugger – TCP 139
Microsoft Visual Studio Remote Debugger – TCP 445

Finally, you may need to set a DCOM exception as listed HERE:

Microsoft Visual Studio Remote Debugger – DCOM – TCP 135

Once all of this is done, you should be good to go for internal pingage and Remote Debugging.