Problem with host names - DNS?

After 15+ years of admin for an Astaro box then a SG 230 UTM, I was brought out of retirement to assist this company with setting up an XGS 2100 on 21.5. It is basically working but there is something I am missing and cannot resolve. This should be simple

I've done the following:
• transferred some configs using the migration tool from Github via SSH
• setup AD sync and imported some groups
• setup SSL VPN for Sophos Connect
• got IP phones, security cameras etc. functioning (hosts/rules/nat)

I believe the resolution to my problem lies in DNS config but can't find it or maybe I've configured it wrong. I've searched the docs ad nauseam.

Problem: users can access network resources, but for things like RDP, mapped drives etc., the machines won't see internal host names. Instead I am using IP addresses. I need to correct this as there are ancillary network functions that need to see the host names.

I appreciate any help on this.



Added v21.5 tags
[edited by: Erick Jan at 3:24 AM (GMT -7) on 21 Jul 2025]