Fanvil X7C via VPN / Registration periodically fails

[Flite]

Dear all,

I have the following configuration:
- 3CX Professional, 16.0.7.1078
- Windows Server 2019 Standard, running on HyperV
- 6 Fanvil X7C Phones in the local LAN (using the suggested firmware by 3CX: 2.2.11)

We decided to use the Fanvil Phones, because 3cx recommended them. We have an external office, where we want to connect more Fanvil X7C phones. Both offices are connected with a site-to-site IPsec VPN. The main office (office 1) has the following network: 192.168.5.0 (3CX Server 192.168.5.4, Gateway 192.168.5.254), the external office (office 2) the 192.168.3.0 (Phone is 192.168.3.44, Gateway 192.168.3.1).

The phone is autoprovisioned by adding the following link into the Fanvil X7C configuration: http://192.168.5.4:5000/provisioning/kdmc6wjpfpj16u The provisioning just works fine.

The phone connects and works without any issues as expected. But after some hours suddenly, the display shows "SIP Register Failed". The phone doesn't work anymore. If I unplug the phone and restart ist, everything works fine again for some hours.

I realized, that 3cx shows the phone with the ip address of my gateway in office 1 (192.168.5.254) instead of the ip address of the phone (192.168.3.44).

Could you give me some advice, what happens here or how to fix it?

Thank you in advance!
Best regards from Germany
Steffen

 

[JohnS_3CX]

Hi Steffen,

Since you have a site to site VPN, it would be a good idea to compare the same phones that are at the main office, and connected locally to the PBX (not via VPN).

If you find that the remote phones lose their registration, but the local phones don't then you will have to start looking at your network setup for clues.

The fact that they reconnect after restarting them may be an indicator that the logical connection does not stay up and the traffic is no longer passing through until some event triggers it again.

You might want to take a look at this post to get some ideas
https://www.3cx.com/community/threads/causes-of-sip-phone-de-registration.78907/#post-362731

 

[Flite]

Hi John, thank you for your quick answer.

As the local phones don't have that issue, it is likely to be the VPN setting that causes the error. My thoughts:
- I will check the VPN logs for disconnections
- I added a syslog server on debug level to the Fanvil X7C in the remote location (office 2). When the registration fails again, I can (hopefully) see the error messages of the phone.
- What would happen, if the VPN connection is disconnected an 5 min later connected again? Would the Phone register automatically again? Because the "SIP Register Failed" Messages stays at the display.

 

[JohnS_3CX]

Hi Steffen,

Normally the phone will try to reconnect, but it largely depends on the network conditions as this will go.. It may give up after a while of not being able to reach the PBX, or exponentially back off from trying to register again.