Session Traversal Utilities for NAT (STUN)

Polycom UC Software supports Session Traversal Utilities for NAT (STUN), a network protocol used in NAT traversal for real-time IP communications, such as voice, video, and messaging.

You can configure the phone to act as a STUN client to send request to STUN Server to discover the public IP and port(s). You can also configure the phone to send keep-alive messages to refresh NAT bindings.

STUN does not work if the NAT device is symmetric. This may be a drawback in some situations as most enterprise-class firewalls are symmetric.

Note: When STUN feature is enabled, Polycom doesn’t recommend video calls on VVX 500 and 600 business media phones.