Yealink phones don't come back after internet outage

[Peter Richardson]

Hi All,

So we're still having this issue with same title here (thread is now locked so can't keep that conversation going):
https://www.3cx.com/community/threa...-come-back-after-internet-outage.63485/page-2

Seems like nobody actually got anything resolved, including me. This happened again last week - we had some form of outage at the data centre and 3 clients called with "our phones are down again". I told them we had an outage and that rebooting the phones would fix it, which it did. But Why do the phones stop trying to register? And why is it only happening with some Yealink phones/models/sites and not others?

 

[AWS2P]

can it be the register time set too long value who let phone in his state until next register try?

 

[nub]

can it be the register time set too long value who let phone in his state until next register try?

https://www.3cx.com/community/attachments/2u7vgk-jpg.9622/

 

[BrenttG]

I have seen this occur at a site we manage, and it turned out to not even be a 3CX issue, but instead it was DNS. The Internet would go down for an extended period, and the local DNS server would fail to resolve the 3cx servers FQDN, thus the phones, which had been provided the local DNS servers IP for their DNS by the DHCP server, could not resolve the PBX.

The fix we came up with was just hard coding the FQDN of the 3CX server to its proper external IP on the local DNS server, this resolved the issue for the phones, as for some reason once the local windows DNS server which we had no control over would fail to resolve the 3cx fqdn for a while, it would give up and cache the fact that it didnt seem to exist, rebooting the server once the internet was back up would resolve it, but having them reboot the server every time the internet goes down isnt a fix either. So like i said we hard coded it. Now the phones all come back online within a moment of the internet returning.

So i strongly suggest you consult the local DNS server if there is one, and try hard coding the record and see if the issue vanishes.

 

[Mark Phillips]

You may well be on to something there with the local DNS server. Back in February I experienced the same issue with a pair of Yealink T40Gs failing to re-register after an internet outage. We have a local DNS server on site and it is likely that at the time, the phones were provisioned with our 3CX FQDN.

Since February I have not experienced the same issue, and we have been provisioning all phones with the internal DNS name of our on-premises 3CX server - which statically resolves to its internal IP address.