What is a STUN Server?

A STUN (Session Traversal of User Datagram Protocol [UDP] Through Network Address Translators [NATs]) server allows NAT clients (i.e. IP phones behind a firewall) to setup phone calls to a VoIP provider hosted outside of the local network.

The STUN server allows clients to find out their public address, the type of NAT they are behind and the internet side port associated by the NAT with a particular local port. This information is used to set up UDP communication between the client and the VoIP provider to establish a call. The STUN protocol is defined in RFC 3489.

The STUN server is contacted on UDP port 3478, however the server will hint clients to perform tests on alternate IP and port number too (STUN servers have two IP addresses). The RFC states that this port and IP are arbitrary. STUN functionality is seamlessly handled by the 3CX software that C2 Communications relies on.

Related Blogs

An Overview Of Microsoft Teams Calling Security

In today's ever-evolving digital environment, the significance of secure communication cannot be overstated, particularly for businesses. The protected exchange of confidential data is paramount, and thanks to its robust security protocols, Microsoft Teams emerges as a standout solution.   In this article, we will explore the vital security features that Microsoft Teams...

30/01/2024 | Read more

The Ultimate Guide To Microsoft Teams Calling

In the ever-evolving landscape of business communication, digital technology has revolutionised how we connect, collaborate, and carry out our daily operations. Among the various innovations, Microsoft Teams phone calling has emerged as a beacon of transformation, offering a seamless and integrated communication experience. This article explores the heart of Microsoft Teams phone...

12/12/2023 | Read more

Proven Communication Strategies for Remote Teams

As a result of the pandemic, more and more businesses have embraced remote working, bringing about a major change in our work culture. This trend is altering how teams interact and collaborate, highlighting the importance of effective communication as a key factor for success.   Common Challenges Of Remote Communication Communication can...

02/11/2023 | Read more