SIP registers okay first time after startup, but each subsequent register fails

[Luqadoo]

From the Activity Log after startup:

12/15/2020 1:17:11 PM - [CM504004]: Registration succeeded for: Lc:10000(@WOW Business[<sip:[email protected]:0/UDP>])

About two minutes later:

12/15/2020 1:18:08 PM - [CM504005]: Registration failed for: Lc:10000(@WOW Business[<sip:[email protected]:0/UDP>]); Cause: Cause: 408 Request Timeout/REGISTER from local

This issue is repeatable - we can reboot the computer running 3CX PBX, the SIP trunk will register okay, we can receive phone calls for about two minutes before the 2nd register occurs. The 2nd and each subsequent register fails and we can no longer receive phone calls.


Has anyone encountered this behavior before? What is the fix?

 

[leejor]

Two minutes seems to be an awfully short time for a re-registration to happen. Is this a time you have manually set, or is it set by your provider?

 

[JohnS_3CX]

Please read this post and provide additional information about the system
https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

 

[Luqadoo]

Please read this post and provide additional information about the system
https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

• 3CX Version: Standard Annual 16.0.1078
• Server OS: Windows 10 Pro
• Is the 3CX Server Hosted and where? Self-hosted, on-premise
• IP Phone Make/Model/Firmware: Yealink SIP-T48S 66.85.0.5
• Provisioning Method: Local / VPN / STUN / SBC: Local
• Trunk Provider or Gateway Make/Model: WOW! Business
• Has the Firewall Checker passed: Yes
• Are custom Phone Templates being used: No

 

[Luqadoo]

Two minutes seems to be an awfully short time for a re-registration to happen. Is this a time you have manually set, or is it set by your provider?

This is not a time we have set, it seems to be hardcoded into 3CX. Changing "Re-Register Timeout" under SIP Trunks -> [Name of SIP Trunk] -> Options doesn't seem to have any effect.

 

[YiannisH_3CX]

Hi @Luqadoo

What you set under your trunks settings is a suggestion. The provider will finally decide what the registration timeout should be and the PBX will follow. Some providers accept what is sent to them while others set their own timeout. This is decided in the 200 OK message of the provider that comes in reply to the registration message from the PBX.
You will need to run a packet capture and check what the PBX is sending and what the provider answers back. The PBX should then send another registration message before the time set by the provider runs out. The PBX should send a re-registration attempt when 90% of the agreed time elapses.

 

[Luqadoo]

Hi @YiannisH_3CX

I'm unable to capture the first register packet. I configured Wireshark as a service that runs automatically on startup. But on each reboot, 3CX beats Wireshark to the punch by almost exactly one second each time.

Another remarkable thing I noticed: I never see the 2nd or any subsequent register attempts in Wireshark. If I disable the 3CX service (and also Wireshark), and restart it, there's never a first successful register. It doesn't make a difference if I immediately restart it or if I wait half an hour.

The only time there's a successful register is if the computer is rebooted and 3CX registers within a few seconds of that. I suspect this isn't an issue with WOW, it's more likely an issue with Windows - maybe something to do with the way Windows does networking. Any ideas?

 

[YiannisH_3CX]

You do not need to run Wireshark on boot to capture a REGISTER message. Start Wireshark on the machine and leave it running. Then restart the SIP server service through the management console and wait for the services to restart. Once the services are up you should see your trunk as registered. Wait for the issue to occur and once the trunks goes down stop the capture and save it.

 

[Luqadoo]

You do not need to run Wireshark on boot to capture a REGISTER message. Start Wireshark on the machine and leave it running. Then restart the SIP server service through the management console and wait for the services to restart. Once the services are up you should see your trunk as registered. Wait for the issue to occur and once the trunks goes down stop the capture and save it.

Please read the 2nd and 3rd paragraphs of my previous post.

 

[Luqadoo]

Update: We gave up on Windows. Installed the 3CX Debian ISO and now the SIP trunk registers for longer than two minutes and we can send/receive phone calls with no problems.

Although, it was an ordeal in Linux to get the 2nd Ethernet adapter to work... I suppose the rest of that topic can be for another thread I can create soon if needed.