STUN (which stands for simple traversal of UDP through NAT) is a pragmatic approach to solving the problem of connecting VoIP calls through routers without UPnP ! Please view our technical downloads, which discuss how STUN can help you drive more network minutes, increase customers satisfaction, and decrease your technical customers service calls.

STUN was included in snom4S however with new more secure firewalls it does not work in an ever increasing number of cases and has been obsoleted by products like snom's NATFilter or ABP's NATPASS

Contact ABP to learn more about snom’s STUN server and our other 'Far end NAT Traversal'solutions.

With the increasing importance of SIP, customers are asking for working solutions that can be used in home networks. Home users carrying their VoIP phone home get frustrated if they can’t make phone calls, like they can surf the Internet. This endangers the success of VoIP in the mass market.

Because of the limited range of Internet Version 4 addresses, users need to use private addresses in their installations. Unfortunately, SIP and the media transport protocol RTP assumes that addresses are visible in the public Internet but network address translations (NAT) violates there rules.

The next generation Internet protocol version 6 solves the problems, however, it is not currently deployed. Additionally, UPnP is a good way to control the behavior of NAT gateways. However in some of today’s networks, these protocols are at times not available. By installing a STUN (which stands for simple traversal of UDP through NAT) server you reduce your technical service calls by allowing your network to transfer VoIP through your customer’s LANs in both UnPP and non UnPP environments. At the same time your customer is not required to change equipment in their network. Obviously, not only reducing your technical calls but reducing your customers requirements to buy additional equipment!