Router port mapping for macOS Server
You can manually configure port mapping on most Internet routers by using their configuration software. Usually, the configuration software consists of several webpages. Using a web browser on any computer connected to your intranet, you go to the webpage with settings for port mapping or port forwarding. You must enter port numbers for services and enter your server’s IP address for each one.
For a list of services and the corresponding ports for which you might want to set up port mapping or forwarding, see How macOS Server uses services and ports.