DNS Routing for Internal Hosts

Hello,

We have 3 RED networks (working in split mode) which include multiple windows hosts. The users RDP into those windows hosts. Everything works however, we want to be able to assign hostnames to our hosts so that users don't have to remember the IP addresses of each host and can simple type in the hostnames in the RDP app to log in.

We have configured the UTM in the following manner:

1. Under Network Services > DNS > Global Settings > We have included all our internal networks (i.e. all the RED networks) in the allowed networks
2. Under Network Services > DNS > Forwarders > We have added Google DNS (8.8.8.8) as the host and have unchecked "User forwarders assigned by ISP"
3. Under Network Services > DHCP > The DNS for each interface is set to be its own address (for example - 20.20.20.1 RED has the DNS set as 20.20.20.1)
4. Under Definitions and Users > Network Definitions > For each host definition, we have specified a unique hostname under the DNS section

As per our understanding, this should work. However, when users type in the hostnames in the RDP app, the REDs are not able to resolve its IP address.

Any suggestions?

Thanks!