I have recently set up a Windows Server 2016 box with RRAS to act as the router for my network. I do not have static IPs, and there are a few ports I need to forward from the external interface (connected directly to modem in bridge mode) to another machine. This works fine over the Internet, just going 1:1 via NAT for the ports and using dynamic DNS on the router box.
However, machines inside my network cannot reach the dynamic DNS address. They can access the machine hosting the service directly, but this basically means they need to use two addresses (one for inside the network, one for outside) and that is a hassle.
Is there any way that I can make my dynamic DNS reachable from inside the network?