A Session Traversal Utilities for NAT (STUN) server facilitates the traversal of Network Address Translation (NAT) and firewalls by Network Address Translation Traversal (NATT)-aware clients.
It’s a vital component in establishing real-time communications such as voice, video, and interactive gaming sessions. The STUN server works by providing the client with its public IP address and port, which allows the client to configure its firewall or NAT device to permit incoming traffic from the other participants in the communication session.