Symmetric NAT Traversal

Tmedia supports passive NAT Traversal that addresses the need of peer VoIP endpoint having a private network address. This endpoint device is situated behind a NAT (Network Address Translation) device, e.g. Firewall, while the Tmedia VoIP port has a public IP address. For the passive mode, TMG detects the received RTP packet's source IP address and port. In response, Tmedia uses this source IP address and port as the packet destination for RTP.

TelcoBridges and Passive NAT Traversal

Tmedia supports passive NAT Traversal starting from Tmedia release 2.6.31. Please refer to TMG-CONTROL version 2.6

Typical Use Case

Important Reminders

• All devices in the path must support symmetric RTP/RTCP: RFC 4961
• Currently, TMedia does not support advertising itself behind a NAT (Active NAT Traversal)

How to enable passive NAT Traversal

• This feature is to be enabled per SIP NAP
• Go to NAP -> Edit -> NAT traversal -> Check "Enable"
• Save and activate your configuration

External Sources

• RFC 4961 Symmetric RTP / RTP Control Protocol (RTCP)