No Audio with one windows client post update 6

[Chris Cuatt]

Was running update 5 with no issues. Updated to update 6 and edited the watchguard policies to include the new audio ports. Things run great for half the day... I make/receive calls with no issues... Then the next call I make, I have no audio..., whether I'm calling extension to extension or calling in or calling out. Multiple other 3CX clients in same network not having audio issues. The only difference is I only use a soft phone and use a Sennheiser head set.

This is what I have:
Windows 10 Pro Fully patched
Sennheiser SD BS, USB attached to laptop. All drivers, firmware up to date
Latest 3CX Windows Client
I'm the 3CX admin for our company, as well as the others we support.

When I connect my Win 3CX Client to our PBX I have no audio... I connect my same client to another PBX on update 5 and have audio. I connect to our test 3CX with update 6 and have audio. I connect my laptop to my cell phone hotspot and have audio.

While connected to our production 3CX and making an external test call the following is being blocked on the watchguard firewall (the same firewall and same firewall policies the test environment uses) See attached...

While making an internal, extension to extension call, the following is being blocked... see attached.

Why is the PBX trying to talk to my PC over port 42xxx? 42xxx aren't listed as ports 3CX uses.
Why is my 3CX client trying to talk to the PBX over port 8xxx? 8xxx ports aren't listed as ports 3CX is using...

I haven't opened those 42xxx and 8xxx ports on the firewall yet... I'm sure if I do, I'll get audio, but why are these ports being used?

Let me reiterate that we've been using Update 5 since it came out with no issues... In fact, we've used 15.5 since update 1 with no issue....

Any help will be appreciated.

 

[Craig Hollins]

We have had similar reports with SP6. I have two completely independent systems that suffer from no audio on a random basis. Restart the services in the console and it all works again. This is happening two to three times per day and it seems to affect only STUN remote phones.

3CX support's only response is to do a wireshark capture - of an intermittent problem - which requires a restart of the server - on a live production system.

 

[Chris Cuatt]

For those paying attention, and to help those who are having this issue, here's the 3CX response to a ticket I opened. My responses are next to it.


• The PBX internal ports were expanded from 7000-8499 (in SP5 and above) where is this documented? I have went through the entire change log for update 5.

• The 3CX phone for windows is using random high ports (above 40000) Need a range and again, where is this documented?!? Please provide links

• In the provided pcap, there is no audio from the 3CX client (see screenshot).

 

[Cyberdoc1325]

I've the same problem have you a solution ? I must restart everydays my PABX since Update 6
I'm waiting for a solution and i provide PCAP files.

 

[Chris Cuatt]

Our solution was to open up ports 42000-43000 and 7000-8499 between our 3CX VLAN and our PC/Server VLAN on our Watchguard firewall.

3CX needs to do a much better job of documenting port requirements.

Edit: UDP ports

 

[Lee Cramman]

For problems with silent audio my first "port" of call is always the firewall checker.