Allowed Hostnames Issue

[mohkhalifa]

Dear All,
I am facing a problem that we using some services in our production like time sync (NTP) and security updates ...... etc and they must be always connected to the internet to all of the devices.
I added all the FQDNs to the "Allow Hostnames" in my CP as my CP is configured to my LAN network to bypass that FQDNs from the CP authentication. BUT the problem, all of these services are always changing there IPs and they can't work properly.
Please Advise!

[mohkhalifa]

Your soonest HELP is highly appreciated