SIP trunks, inbound and outbound calls disabled somehow!

[sconno71]

This morning a client was able to receive calls from SIP trunk, however outbound calls simply dropped.
I logged in and after a short while discovered that SIP Trunk / Options / Call Options, "Allow inbound calls" and "Allow outbound calls" were no longer selected.

I selected them both and saved the config and outbound calls were fixed for about 2 hours, I checked all the logs and there were no recorded trunk changes since 16th June.

The next fault was inbound calls were perfect, but outbound calls had no audio but the call was established to the called party. I checked the event log, and there had been no changes recorded since the fix 2 hours earlier. For the life of me, I could not diagnose even with the assistance of the SIP trunk provided what was wrong, and in desperation I restored the 3CX from backup and everything is working again.
As a precaution I have disabled Instance Manager and changed the admin password.

How can these settings be changed without something appearing in the logs?
I have console restrictions to 4 IP addresses.

SIP helper / ALG is disabled on all routers and there is no firewall on the hosted VM other than what comes with 3CX (Anti hacking etc etc).

3CX Version: Enterprise Annual 18.0 (Build 461)
Server OS Debian 9
Hosted in NextDC
Yealink T46U version 108.86.0.72
Provisioning Method: SBC
Trunk Provider: Launtel
Has the Firewall Checker passed: YES
Are custom Phone Templates being used: NO

 

[Alphabetic]

Could be some routing issue in NextDC - I would reach out to them an ask if they had issues.

 

[Charles_3CX]

Regarding the Sip trunk, is this an IP-based trunk (no registration)?

 

[sconno71]

Regarding the Sip trunk, is this an IP-based trunk (no registration)?

Correct Charles.
I have just checked this morning and the fault had returned. No audio on outbound calls. Inbound calls are fine.
I rebooted the VM, fault remained.
Restored this mornings 1:00am backup and the fault remained.
Restored the 9pm backup I did last night and the outbound audio is now working again, so I guess something happened between the two backups.
Like before there is nothing in the logs to indicate that any changes have been made to the 3CX configuration.

 

[Charles_3CX]

Can you double-check the OS version as you mentioned it to be Debian 9 and you are on version 18, which you should actually be using Debian 10 and not 9?

Regarding the fact that the Allow inbound calls" and "Allow outbound calls" were no longer selected did you press disable all under the trunk settings? Check the audit log for this, but if you are not on Debian 10 then this will need to be re-deployed to a new machine using a supported deployment method taking a backup and restoring it to a new machine that will be debian10.

 

[sconno71]

My apologies Charles, I am using Debian 10. Issue just happened again not 10 minutes ago, no audio on outbound calls. Restored again it back up and running. No entries in the logs regarding any changes, audio just stopped on outbound only.

lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 10 (buster)
Release: 10
Codename: buster

Your other question was answered in my original post "I checked all the logs and there were no recorded trunk changes since 16th June."