2 out of 4 Lancom SIP Trunks no longer functional after backup.

[Slideform]

Hi there,

I've got a big questionmark on my head I cant get rid off...

Last week I transfered a pbx to a different computer. Source and new Server both use Hyper V.
Installing the linux pbx template and importing the exported config was no problem.
After importing it some testcalls were made and so far anything is ok...or so it seemed.
Router is a Lancom which provides the SIP Trunks via VCM.
We have 4 identically set up Trunks with numbers: 2006,2007,6087570 and 6087571.

After importing the config 6087570 and 6087571 couldnt be called anymore. The two SIP Trunks wont connect.
I changed nothing but the machine the pbx is running on. Both machines have 192.168.1.xx network.

Any ideas? If all 4 would no longer work, I would've at least something to start with, but this way just doesnt make sense.

 

[ChrisC_3CX]

First off, did you use the 3CX ISO to deploy this new 3CX PBX?

Regarding the SIP Trunks, what type are they, IP Based or Register based? Is there a specific reason you are using 4 separate identical SIP Trunks instead of adding the other numbers as DIDs all on one SIP Trunk?

In regards to the issue, what happens exactly? Are you unable to both receive and place calls through those SIP Trunks or do they appear as unregistered(red)?

 

[Slideform]

Hi Chris,
thanks for getting back to me.
Yes I used the newest 3CX ISO.
They are register based.

I didnt set up this pbx...the one who did is no longer in my company. But since he had years of experience using 3cx in different environments, I'd assume there is a reason for this setup.
A lot of questions arise concerning this particular pbx, especially because I'm still learning.

If there is a way to add the non connecting SIPs to the other functional ones with lancom, I'd be happy to know how.
Just adding the DIDs to my existing/working SIP Trunk didnt work unfortunately.

Outgoing calls/rules are all made using the Number 2006. I would test to call someone using 6087570 but since the SIP Trunk are unregistered, this would not work yet. So far calling or being called doesnt work.

 

[Slideform]

If I change the connection type from register based to IP-based they SIP Trunk turns green, but calls still dont get through.

 

[ChrisC_3CX]

If the affected SIP Trunks are Register based but unregistered, there's not much you can do via 3CX but make sure that the two affected SIP Trunks are configured correctly. As this is not a supported provider that has been tested with 3CX, we do not have a configuration template and can't really know what configuration is required. Since the issue occurred after migrating to a new machine do check if changes such as changing the local IP of the host machine may be contributing to the issue. You might want to consider also contacting the provider if unsure of the required configuration.

If you wish to have a look at our currently supported SIP providers who have been tested with 3CX and therefore offer a more trouble-free experience, you may check the following link: https://www.3cx.com/partners/voip-providers/

 

[Slideform]

I got it. It was a shot into the blue but they sometimes hit something too i guess.

I changed the transport method in my SIP Trunk options from TCP - > All.
Why exactly this resolved this issue is still unclear though. Any thoughts?

 

[YiannisH_3CX]

By doing that change the PBX will not try to connect via UDP and then TCP. I am guessing TCP was not working but UDP did. For why this happened you should ask your provider. Perhaps they do not accept multiple trunks on the TCP connection. Glad to see its now working though.