Does anyone know how to set our 2820 so that it does not block remote assistance via Windows Live Messenger? It seems to work if the other person has a VPN connection but not otherwise.
Any help gratefully received

Have you added the remote IP to the access list?

We have a number of out-workers who use different PCs sometimes, so it's not practical to enter their IP addresses to get them through. We found the best method was to set the 2820 to allow pass-through and then control them via our netwrok policies