3CX not registering depending on outbound proxy name

[Richard.B.]

Hello,

I am unfortunately experiencing a weird issue with the newest stable release of 3CX (16.0.1078). I am trying to register a Deutsche Telekom Company Flex SIP Trunk (by the way, I was told by Deutsche Telekom officials that they will eventually migrate everybody to their new "Company Flex" SIP trunk, which implies that at some point there should really be a template for this). However, 3CX is not showing any error and is just doing nothing. As soon as I set the outbound proxy to the one specified by DTAG for the trunk, I get no response in the event log, and it seems, as if 3CX is not even trying to register. As soon as I change the proxy, it at least gives me an error. Therefore, I think that there is something wrong with 3CX, while it's not yet clear that this issue is entirely to blame on 3CX. But I think there should at least be a response in the GUI, if something fails, rather than it sitting there doing nothing.

Thank you very much in advance.

Richard Braun

 

[leejor]

Are you looking in the 3CX Activity Log, or the Event Log? The Activity log is the better troubleshooting tool.

 

[cobaltit]

I can assure you that 3CX is complying by SIP standards. So if you are using what is technically an unsupported provider because of the change they made, you need to get them on the phone while you are trying to register/make calls. And there is something in management console telling you the status. That would be the red or green circle. If you want more details, you need to turn us wireshark.

 

[Richard.B.]

Are you looking in the 3CX Activity Log, or the Event Log? The Activity log is the better troubleshooting tool.

ActivityLog. There‘s no attempt to register.

 

[Richard.B.]

I can assure you that 3CX is complying by SIP standards. So if you are using what is technically an unsupported provider because of the change they made, you need to get them on the phone while you are trying to register/make calls. And there is something in management console telling you the status. That would be the red or green circle. If you want more details, you need to turn us wireshark.

Thank you for your answer, but you didn‘t get my point. There is no timestamp for „error“ appearing. This seems to be related to other issues where the DNS lookup fails. Even in this situation, there should be an error timestamp in the trunk section in the web interface. I‘ll update this with evidence (capture)

 

[cobaltit]

I know 3CX removed some things from showing in the logs (like extension registering/unregistering) because they prefer troubleshooting to be done in other ways outside of 3CX (like wireshark). If you are referring to the activity log have you turned the logging level up to verbose?

 

[Richard.B.]

I know 3CX removed some things from showing in the logs (like extension registering/unregistering) because they prefer troubleshooting to be done in other ways outside of 3CX (like wireshark). If you are referring to the activity log have you turned the logging level up to verbose?

Yes, done that, but you are right. There I can see the message "registration postponed untill destionation could be resolved". That means, that 3CX is technically fine, but I think that this is in fact nothing that should happen (e.g. that the name cannot be resolved). To me, it would make a lot of sense, if there would be an "error timestamp" shown in the trunk section in the web interface.

 

[Richard.B.]

So, first off, I want to sincerely thank everyone wo helped troubleshooting this. I also want to provide users experiencing this with what caused the issue, so that I can hopefully save them some headache:
The DNS resolution of the Company Flex trunks works quite a bit different from the one on the old Telekom NGN trunk. When we tried to conenct our 3CX which is running behind a pfsense firewall and uses a Windows Server DC for the DNS resultion, the outbound proxy (<companyID>.primary.companyflex....) could not be resolved. We were able to fix the issue temporarily be using an external DNS server (9.9.9.11). However, this comes with some drawbacks in realtion to QOS in the Telekom networks. Therefore, we are currently looking into why we were not able to use our local resolvers (e.g. pfsense and the Windows Server Domain Contoller). I'll update this post with further information as soon as I can track the issue down. But for now, I want to report that indeed Company Flex is working with 3CX flawlessly. I recommend using the Telekom NGN template with the instructions provided by 3CX on how to configure Telekom NGN trunks with 3CX.
All the best,
Richard Braun