NAT translation not working from inside the network (hairpin condition)

Question

I\'m writing a P2P application. Peers regularly ping a main server to update their current IP/port, so when a peer wants to reach another one it can ask the server for that

Answer 1

Interactive Connectivity Establishment (ICE) was specifically developed for solving that type of NAT problems. It uses STUN and TURN to achieve the result and is used in modern p2p applications. (e.g. Voicechat)

The PJNATH library has a document explaining

unlike standalone STUN solution, it (ICE) solves the hairpinning issue, since it also offers host candidates.