Why registration takes place with an external ip?

Question

Asterisk

Good afternoon! There are a couple of offices connected via gre in one is Aster. Recently, phones from the second one began to fight with an external IP. At first, it helped to enable dhcp on them and the problem went away, but just the other day it returned. The office has microt 2011 and ccr1009 on the Aster side. In general, there are 3 offices, but the problem is observed only in 1. The settings on all ticks in the offices are the same

Answer 1

The issue is resolved by specifying the IP instead of the DNS name as a server on the devices

Answer 2

I don't understand here. what phones began to decide, for whom? Why did phones not have DHCP before? where are the commas?

Answer 3

Check the NAT rules on mikrotiks, maybe somewhere the traffic is natitsya where it should not. If there is no NAT between Asterisk and phones, then try disabling sip processing on Mikrotiks in the IP -> Firewall -> Service Ports section. But if Asterisk uses sip trunks to the Internet, then this may affect their operation.