NAT Traversal

Techniques enabling VoIP traffic to pass through Network Address Translation devices

What is NAT traversal?

Network Address Translation (NAT) maps private IP addresses to public ones, allowing multiple devices to share a single public IP. While useful for IPv4 conservation, NAT breaks VoIP because SIP messages embed IP addresses that NAT devices don't automatically rewrite.

Traversal solutions

STUN helps endpoints discover their public IP. TURN relays media when direct connectivity fails. ICE (Interactive Connectivity Establishment) combines both approaches. SBCs handle NAT traversal at the network edge for enterprise deployments.