You may notice that the Grandstream UCM63XX series IP PBX is accessing certain IP addresses at all times from your router or firewall services. This article explains the purposes of these IP addresses.
It is used in ip2location to query the location of an IP address during UCM system startup and download the language pack corresponding to the region. There is no way to disable this feature.
If TR069 is enabled under System Settings on the UCM and there is no Remote Connect plan, by default, the GDMS server will automatically send this IP address to the UCM, and classic stun packets will be sent to this address. Disabling TR069 causes the UCM to go offline from GDMS and cannot be managed through GDMS.