(Simple Traversal of UDP through NAT) A protocol that allows applications to detect that a network address translation (NAT) is being used. It can also detect the type of NAT and IP address assigned by it. STUN was developed to support interactive, two-way communications over the Internet such as for voice (VoIP) and videoconferencing. The STUN client sends requests to a STUN server, which is typically hosted by the service provider.|
Unlike application layer gateways (ALGs) and Middlebox Communications (MIDCOM), which also support two-way communications through NATs, STUN requires no changes to the NAT. See NAT.