NAT (Network Address Translation)
A technique that maps private IP addresses to a public IP address, allowing multiple devices on a local network to share a single public IP. NAT is performed by routers and firewalls. It conserves IPv4 address space but complicates peer-to-peer connections and protocols like SIP and WebRTC. NAT traversal techniques like STUN, TURN, and ICE help establish direct connections through NAT boundaries.