I'm not sure that helps me. My question was pretty bad - more rhetorical than precise.
I hear what you're saying, but I'm not sure MSN Messenger works with NAT routers at all the more i think about what is going on. I'm resisting combing the web for an authoritative list of the voice, voice call, video and file transfer ports used by Messenger.
If it truly is "just" a port issue, and I don't think it is, what ports then would I open to appease MSN Messenger?
A Google search (including a search of MS Knowledgebase)has given me conflicting port numbers - perhaps there was a change - and I found none used by the "send webcam" or "video conference" function.
Is this a port or NAT issue? If port, which ports in which directions for which protocols need to be opened? If an issue with NAT routers, then I am screwed. NAT is a good thing, a natural firewall and I don't want to alter that router setting.