STUN ( on Common Common )

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What is STUN?

STUN  stands for Session Traversal Utilities for NAT.

It is a network protocol helping the end hosts to discover their public IP addresses when located behind a NAT.

STUN is used to permit NAT traversal for real-time voice, video, messaging, and other interactive IP communication applications.

Usually, if Zoiper and the VoiP server are located in the same network, or if public addresses are used, STUN is not required.


All Zoiper products support our backup STUN server (, however if your VoIP provider is running their own STUN server, use it instead.


Default STUN values:

Server hostname /IP
Port : 3478 UDP/TCP
Refresh period : 30


Configuring, disabling and enabling STUN:

Zoiper Classic

Zoiper 3

Zoiper 5

Zoiper for Android

Zoiper for iOS

Zoiper for Windows Phone Mobile

Zoiper WEB (npapi)