By default, any computer on the local network gets assigned a new (local) IP address everytime they connect to the system. We can check the local IP address by typing
In my case, the local address is 192.168.0.8. Since we will want to connect to the server from other computers on the network without changing the target IP address every time, we can assign a static IP address to the server.
This is done by changing the DHCP settings in your router. Usually, the router settings can be changed through a web interface, in my case this can be reached by typing 192.168.0.1 into a web browser. Set up DHCP reservation such that the server always gets assigned the same IP address. While we are at it, we'll also set up port forwarding to make the server available for SSH outside the network and forward por 22 (the SSH port) to 192.168.0.8.