825 bytes added,
18:42, 9 April 2021 NAT Traversal protocols are heavily used for audio and video conferencing (like Jitsi or WorkAdventure used in [[Virtual]]).
== Protocols ==
=== STUN ===
[https://en.wikipedia.org/wiki/STUN STUN] ([https://tools.ietf.org/html/rfc5389 RFC5389]) is used by clients to figure out which IP and port their traffic if being natted to.
Ports: 3478 for UDP and TCP, and 5349 for TLS
=== TURN ===
[https://en.wikipedia.org/wiki/Traversal_Using_Relays_around_NAT TURN] ([https://tools.ietf.org/html/rfc8656 RFC8656]
) is used as fallback for relaying traffic between clients when NAT traversal using STUN failed.
By default, TURN runs on the same ports as STUN: 3478 for TURN over UDP and TCP, and 5349 for TURN over (D)TLS.
== Troubleshooting notes ==
Tcpdump capture filter: <pre>port 3478 or port 5349 or port 19302</pre>.