Network Address Translation (NAT) is a method used in networks to modify network address information in IP packet headers while in transit, allowing multiple devices on a local network to share a single public IP address. This process enhances security and conserves the limited number of available IPv4 addresses by hiding the internal IP addresses from external networks.
Session Traversal Utilities for NAT (STUN) is a network protocol that allows devices behind a NAT (Network Address Translation) to discover their public IP address and the type of NAT they are behind, facilitating peer-to-peer communication. It is crucial for applications like VoIP and video conferencing, where direct communication between clients is necessary despite NAT restrictions.