NAT traversal

Nat Traversal is a way that lets two computers that are far away talk to each other. It's like using a phone. When one computer wants to talk to the other computer, it has to "call" the other computer. It can't just magically talk to it without calling, because usually the other computer is far away. Nat Traversal is a way to make sure the two computers can already talk and when one calls the other, it actually works and the two computers can have a conversation.