Solved Opening a port on my router

Either of those pages would work, just set UDP if you have no plans on using something like Rust:IO. The port would be your main server port, which the default is 28015. If you use the settings in the first image, you'd need to set the LAN IP for your computer hosting it, with the port options being the same. Once you're ready, toggle the Status to On and Apply.

 

Sounds like it is working then. It may take a little bit for your client to show the server, but I'd try restarting the client if you haven't already.