BitTorrent - How do peers connect to each other?

Question

How do peers connect to each other even if they are in separate private networks behind a NAT?

Answer 1

BitTorrent requiers Port Forwarding through NAT to work effectively. some clients and home routers allow the use of UPNP to automatically create port forwarding rules, but there must always be a port forwarded on both sides for BT to work as designed when NAT is in play. Note, BT can "work" without being completely configured. in order to Seed, you must have a port that will accept incomming connections, but that is not strictly a requirement to DL content, since those streams are usually initiated from inside your NAT.