If you are looking for a VNC client, the open source Chicken client supports connecting to specific ports.
You can install Tiger VNC via the brew project with:
brew install tiger-vnc
macOS Built-in Screen Sharing
Alternatively, you can use macOS's built in Screen Sharing application to connect to specific ports via a well formed URL, such as
For VNC servers, other than the built-in macOS VNC server, take a look at OSXvnc.
You could take a different approach and tunnel the existing VNC service through
ssh or another tool. This would expose the VNC service through any port you desire without needing a special VNC server.