About 3cx tunnel protocol:

[C-SP]

Hi All,

I would like to know about 3cx tunnel protocol.

I have issues for one way audio sometimes and if ringing several remote extensions and then one extensions will pick up call then doesn't stop ringing on other extensions sometimes.

I checked packets for trouble shooting with tcpdump for 5060 but it captured only between 3cx to carrier.
According to document 3cx use protocol called "3cx tunnel protocol" with port 5090.

Is this proprietary protocols and encrypted?

Regards.
Michiteru

 

[JohnS_3CX]

Hi Michiteru,

Are you using STUN provisioning on the phones?

 

[C-SP]

Thank you for reply.
customer use Windows legacy app and android app.

 

[JohnS_3CX]

The problem you described with extensions not ringing is very likely caused due network issues

Phones keep ringing
- When you call a ring group for example, everyone gets an INVITE.
- As soon as 1 person answers, the others will get a CANCEL but if this message does not reach them, they will continue to ring because they did not know that.
- Android phones will receive the notice via Google PUSH message. If the PUSH message is not received the phone will not know to stop ringing.

One way audio
Check whether this problem happens only with external calls. If this is true, then probably have to investigate with your carrier/trunk provider. A capture from the PBX should contain the trunk call so you will know whether the audio reached 3CX.

And yes, the protocol is proprietary and encrypted, but if you run a capture using the "All interfaces" option you will see the tunnel traffic too in the 127.0.0.1 range