Dial Delay on internal and outbound calls

[IanT]

As per this thread we having the a similar issue https://www.3cx.com/community/threads/inbound-and-outbound-calls-delayed.65417/
When dialling out there is a 4-6 second delay between pressing send on the phones ( Yealink T42S ) and ringing starting (also affects dial features like call pickup 20 ) . On testing we have found that changing the phones from using the FQDN of the 3cx to the IP address of the server makes the issue go away .
Current setup is 3cx in High Availability ( So FQDN is required ) , both 3cx servers on the same Lan ( but that is not an issue) . Using a Sophos UTM9 firewall , client manages this .
So the delay appears to be connected to DNS , anyone got any thoughts on how to resolve?

 

[JohnS_3CX]

Hi @IanT

Based on the fact that changing to a direct IP the delay goes away, it sounds like your DNS resolution is slow for some reason.

It would be a good idea to run a capture on your PBX, to see if the invite arrives after the delay period or whether it arrives on time but the phone is delayed from the PBX onwards (while using FQDN on the phones of course)