[ztetranz]

Here's an off-topic but somewhat related question that I've been meaning to ask somewhere.

How do "plug and play" consumer devices that receive an incoming call / connection work behind the typical home NAT router? I have an OOMA VOIP phone service which is plugged into my home router with no ports forwarded. It has no trouble receiving an incoming call.

Does it simply open an outgoing connection and hold it open indefinitely?

[aliqot]

STUN or an intermediary

[wmf]

Yes, that's pretty much the only way it could work.