STUN is a toolset for NAT traversal in IP networks. Originally it was intended for usage with UDP datagrams, but has later been extended to work with other transports, as well. STUN Server Test Suite can be used for evaluating STUN server implementations for security flaws and robustness problems.
STUN - Simple Traversal of User Datagram Protocol (UDP)Through Network Address Translators (NATs)
Session Traversal Utilities for NAT (STUN)
Traversal Using Relays around NAT (TURN): Relay Extensions to Session Traversal Utilities for NAT (STUN)
Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal for Offer/Answer Protocols
NAT Behavior Discovery Using STUN
Managing Client Initiated Connections in the Session Initiation Protocol (SIP)
Test vectors for STUN
Traversal Using Relays around NAT (TURN) Extensions for TCP Allocations
Traversal Using Relays around NAT (TURN) Extension for IPv4/IPv6 Transition
Explicit Congestion Notification (ECN) for RTP over UDP