Handsets not ringing

[doncol]

Hi folks,
We have a few installs that have started exhibiting a similar fault since going to v18. External calls come into the system, but handsets don't ring. In one instance, extension to extension calls work OK, just not calls coming in from outside. The confusing thing is that this behaviour did not exhibit itself straight away, just after several weeks of the systems working fine. In one instance, it seems to have been fixed by moving to Ring Groups instead of Call Queues, but that doesn't work for other instances.
Any clues?

 

[leejor]

A bit more information would be helpful...

https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

Are your extensions by chance using STUN?

 

[ChrisC_3CX]

As @leejor mentioned, could you first provide more info on your setup:
https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

it seems to have been fixed by moving to Ring Groups instead of Call Queues, but that doesn't work for other instances.

Do you mean you have other 3CX PBX instances that are also facing this issue?

Also, do you have only one SIP Trunk and one DID? If not, do calls to other SIP Trunks or DIDs do the same thing? Where do the problematic DIDs route to(Ring Group, extension, Call Queue, etc).

 

[doncol]

A bit more information would be helpful...

https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

Are your extensions by chance using STUN?

No. The problem was evident for internal calls (extension to extension) as well as external. What we have now found is that the DNS resolver was not setup correctly (/etc/resolv.conf) on the 3CX PC-Debian Linux,

 

[doncol]

As @leejor mentioned, could you first provide more info on your setup:
https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/


Do you mean you have other 3CX PBX instances that are also facing this issue?

Also, do you have only one SIP Trunk and one DID? If not, do calls to other SIP Trunks or DIDs do the same thing? Where do the problematic DIDs route to(Ring Group, extension, Call Queue, etc).

Yes, it was behaving the same for different installs in different sites. There was a multi SIP trunk site, as well as 2 single SIP trunk, single DID sites. There were a couple of things we found that helped and/or fixed the issue. DNS resolution (/etc/resolv.conf) on the 3CX PC was not referencing the correct DNS server in one instance.
On another installation, changing the SIP trunk to only use IPv4 for IP Mode, and the transport protocol to 'Any' seemed to fix it. We previously had an instance with a single handset that would have audio issues, and sometimes wouldn't get a DHCP lease. We found that disabling CDP on the handset fixed it, so we created a custom template with CDP set to disabled by default and reprovisioned the handset using that and it hasn't been an issue since.

 

[ChrisC_3CX]

There were a couple of things we found that helped and/or fixed the issue. DNS resolution (/etc/resolv.conf) on the 3CX PC was not referencing the correct DNS server in one instance.
On another installation, changing the SIP trunk to only use IPv4 for IP Mode, and the transport protocol to 'Any' seemed to fix it.

DNS issues or SIP Trunk configuration issues would most probably result in SIP Trunk failure altogether so I can't really say this would directly affect handsets in any way such as preventing them from ringing. Also, almost definitely unrelated to the v18 upgrade.

We previously had an instance with a single handset that would have audio issues, and sometimes wouldn't get a DHCP lease. We found that disabling CDP on the handset fixed it, so we created a custom template with CDP set to disabled by default and reprovisioned the handset using that and it hasn't been an issue since.

For issues like this I'd actually recommend investigation on the network level as it would seem that it is the network configuration that is the of of the issue rather that 3CX or IP Phone configuration. Using workarounds such as creating custom templates would not only render those IP Phones unsupported by 3CX but would also potentially leave room for more issues in the future.

In any case, from your last two replies I take that this has now been resolved correct?