Remote Assistance in XP!!!

I need someones help I have installed a router into my network and now remote assistance will not connect. What I need to know is what port does it use to connect to the other computer so I can open that port to the internet in my router settings. Any help would be greatly appreciated thanks.

Remote Desktop and Remote Assistance (as well as Fast User Switching) are both built on Microsofts Windows Terminal Server technology so the port you need to open in 3389.