How does Skype work without port forwarding?

Question

I am designing a p2p application which works on port 30000. My router is not UPnP so I required to forward a port to router. But Sk

Answer 1

Skype works in a very interesting way. From what I've read (and this is a while ago) it works as follows:

• Skype server maintains a list of all users and IPs.
• Skype user A wants to speak to user B
• Skype user A sends a network packet to user B's IP address and waits for a response. (user B never gets this packet).
• Skype user A notifies server of IP/port combination on which it is waiting for a response
• Server notifies user B to send a response to user A on the specified port
• A connection is made.

This is probably over simplified but last I checked, this is how it works. (Someone correct me if I'm wrong).

Edit: fixed bullet issue