STUN Server

[strafelife]

Hello,

I noticed that most blogs and articles here indicate that the STUN server to use is "stun.3cx.com". My question is this: isn't the 3cx IP PBX not STUN capable? Why must we use a 3rd party STUN server?

thank you

 

[leejor]

STUN is a tool that internet devices, 3CX included, can make use of. In some cases , you don't need STUN to be enabled on 3CX.
http://en.wikipedia.org/wiki/Session_Traversal_Utilities_for_NAT

 

[strafelife]

Hi Leejor,

Thanks for the reply, but that wasn't the question. I understand what STUN is, I just wasn't sure that 3cx had a built STUN server. When I enabled STUN on the external hostname of my 3cx host, it wouldn't work. It appears as if the STUN request exits the network (external IP), only to come back to the 3cx host - in principal. My firewall does not allow this behavior without a NAT Reflection in place.

thanks

 

[leejor]

There really would be no reason for 3CX to also act as a STUN server. Besides the two 3CX servers, there are a number that can be used, on the net. It would be like creating an NTP (time) server, there is no need as plenty are available, for free.

When I enabled STUN on the external hostname of my 3cx host, it wouldn't work. It appears as if the STUN request exits the network (external IP), only to come back to the 3cx host - in principal. My firewall does not allow this behavior without a NAT Reflection in place.

If you enable STUN, and you are using any STUN server then the requests should be going to a DNS server, to get the IP, and then off to that STUN server. If your STUN requests are coming back to your 3CX public P , then you really need to check your settings. It may be something to do with your DNS server settings. You could try using a site, such as this http://baremetal.com/cgi-bin/dnsip from the PC you are running 3CX. If you put in the STUN server you are using and it doesn't come back with the actual public IP of the server then it can't reach a DNS server.