Remote ext. on same remote net cannot connect to each other

[WillyVidable]

Hi,

I have a 3CX Phone System running on a virtual machine on my data center and I want to connect all my phone extensions remotely. My users are in several offices with no more than 5 extensions each. I am trying to avoid using the SIP Proxy Manager so for my test I configured 6 extensions on a remote network. I am using YeaLink T22 and T26 phones.

The extensions can call external numbers and can receive calls from outside but extensions cannot call each other localy, when I call another local extension it rings but there is not voice. I configured the phone following the documentation provided by 3CX. For the this test I changed the original Linksys Router and installed a Netgear ProSafe (FVS318) in order for not have issues with all the port handling required.

Any suggestion about where to look for the problem?

 

[SY]

Re: Remote ext. on same remote net cannot connect to each ot

You can choose one of the option:
1. Set PBX delivers audio = on for all remote extensions (audio will go through the PBX server)
2. use tunnel with "PBX delivers audio = off". It will make a shortest possible path of the audio.
3. Build VPN and use PBX delivers audio = off. (not sure that it will help to implement short audio path)
4. use PBX delivers audio = off and find equipment which support "hairpin NAT" which will be able to recognize "local" UDP traffic on external IP and will return it back to the local network.

Regards

 

[leejor]

Re: Remote ext. on same remote net cannot connect to each ot

First off, be sure that all of the extensions have been give different (unique) port numbers. You can try changing the extension settings in 3CX to force the audio path through 3CX.

I have seen audio issues, with multiple extensions behind the same remoter router.

Sometimes it is the result of a particular make/model of router that seems to be unable to route the audio packets to the correct phone. Once you go beyond two remote extension at one location, it is really worth considering the use of the proxy server. An alternative might be a DD-WRT capable router running the VoIP firmware (Milkfish), as it is capable of being a proxy server. It all depends on your current set-up/security/firewall, etc.

 

[WillyVidable]

Re: Remote ext. on same remote net cannot connect to each ot

Thanks SY and Leejor for your answer.

I set up a VPN connection as suggested between my data center and the branch office and then configured the phones as local (not special configurations required) and all is working like a charm.

Thanks a lot for your help.