I have several clients for whom I have established work-from-home RDP
connections. The hardware firewall in the office forwards one specific port
to each of thost WinXP stations behind the firewall. None of these are 3389
because each office has multiple hosts on the LAN behind the firewall. Each
of these hosts has its RDP port modified in the registry to be the same as
the port on the firewall. (MVP's: pardon my lengthy prologue here; I'm sure
you already know all of this).

Here's the question, though: how can I do remote assistance to these
computers from outside the firewall? I can log on remotely via RDP to fix
things, but I cannot do training or interact with the user. It looks to me
like remote assistance runs over port 3389 by default. Or is there a separate
registry entry for the remote assistance port and I just need to open port
3389 on the firewall without forwarding it.