# What is NAT traversal in VoIP?

> NAT traversal is how a VoIP endpoint behind a router (which rewrites private IP addresses) still receives voice media. Because SIP and RTP carry IP addresses inside their payloads, plain NAT breaks the media path; techniques such as STUN, TURN, and ICE — plus a Session Border Controller on the network edge — discover the public address and relay media when needed so audio flows both ways. It is a common cause of one-way-audio faults. See /answers/what-is-sbc, /answers/what-is-webrtc, and /answers/what-is-sip.

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- Last reviewed: 2026-07-22
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## Related

- [All answers](https://www.broadnet.me/answers)
- [Glossary](https://www.broadnet.me/answers)
- [What is an SBC (Session Border Controller)?](https://www.broadnet.me/answers/what-is-sbc)
- [What is WebRTC?](https://www.broadnet.me/answers/what-is-webrtc)
- [What is SIP (Session Initiation Protocol)?](https://www.broadnet.me/answers/what-is-sip)
- [What is RTP (Real-time Transport Protocol)?](https://www.broadnet.me/answers/what-is-rtp)
- [Voice](https://www.broadnet.me/products/voice)