Firewall Checker passes then fails

[AlexanderHanna]

Good day,

I am having a strange issue with one of my 3CX installs. It is version 15.5 SP6 and has been working for some time. Recently we started getting reports of some calls with no audio. The firewall had passed before. As we do not manage the network/firewall, I ran the firewall checker again and it failed. I then went on site and asked the IT department if changes were made to the firewall. They said no. So we ran the firewall checker again, and it passed. This was very strange because I had ran it 2 hours earlier and it had failed. So now I am think that the IT department might have fixed it. However, today the same thing happen, ran the test, it failed; ran the test 5 mins later and it passed. What gives. Something must be happening between the 3CX server and the firewall that is causing this.

Anyone else had this experience, or any ideas as to what this might be?

Thanks,
Alexander

 

[YiannisH_3CX]

Hello @AlexanderHanna

Which ports are failing? Are the same ports failing every time the firewall checker fails? The best way to troubleshoot the issue is to use wireshark as described in the guide below:
https://www.3cx.com/docs/firewall-checker/

 

[AlexanderHanna]

Yes, it is the same ports that fail. But the thing is, I will run the firewall checker and it would fail. Then I run it 5 mins later without doing anything, and it would passed. I will then run the firewall checker throughout the day and it would continue to passed. Next morning I run it, it fails, then shortly after it passes with no issues.

Thanks

 

[YiannisH_3CX]

To see exactly what is going on you will need to troubleshoot the firewall using the guide above. It looks like the firewall is closing the connection somehow after long inactivity periods once you run it the first time it fails but the connection is re-established so the next check passes.