Once the operating system is installed, there is pretty much no more need for keyboard and screen to be connected to it. Unless you have changes to make to the BIOS, all further configuration can be done over the network from now on. You can pack it away into whatever closet or press it is going to live in, leaving only a power cable and network cable connected.
The Ubuntu server operating system does not come with a graphical user interface, or GUI, running by default. A GUI can certainly be installed if needed, but mostly it is expected that you will be using the command line to configure your server. You connect to your server using the Secure Shell, or SSH, protocol, a networking protocol which allows you to send commands over the network securely and without anyone being able to intercept and see what you are typing. SSH is a successor to the original networking terminal protocol, Telnet, which was not run over an encrypted connection. Once internet networking took off, the lack of security in Telnet became a big hurdle, and SSH was developed to run over a secure, encrypted, session, so any passwords, etc, could not be sniffed on the network.
For a Windows computer to connect to your server, you will need to install a program which can communicate over SSH. I believe Mac’s have this capability built in, but as I am not as familiar with Apple computers, I’m going to focus on Windows machines. You also need to know the network, or IP (Internet Protocol), address of your server, to connect to.
Probably the most well-known SSH/Telnet client for Windows is PuTTY. Go to the PuTTY site and download and install the Windows installer package. Once installed, call up the PuTTY interface to make the connection.
The two things you need for your SSH connection are the IP address and the port number. To take the port number first, network services run over different ports, which allows many services run over the same network connection without getting in each others way, in a similar way to how different TV programs are shown on different TV channels, despite all using the one cable. SSH runs over port 22, and Telnet runs over port 23.
To get the IP address of your server, there are a number of ways you can do this. If you haven’t packed away the keyboard and screen yet, you can run the ifconfig command to see what IP address has been assigned to your server. In the example below, I have two network interfaces – most likely your server will have two also. One is the loopback interface, lo, which is just a way for the network card to send a signal back to itself, for testing purposes, etc. This is always going to be 127.0.0.1. The other one, p4p1 in my example, is your real network interface. Look for the entry called ‘inet addr:’, and that is your IP address
Another way to check the IP of your server is to log into your home router. IPs for computers on your home network are often assigned by your router, that is often the gateway device between your home network and the Internet. It may have a menu of assigned addresses, from which you can spot an entry for your server.
You can also install a network scanner on your Windows computer or phone. Examples for the computer include Angry IP Scanner, and for phones would be Fing (IOS or Android).
Once you have your server IP address, enter it into PuTTY, tick the SSH protocol box and press Open. If the details are correct, you will be presented with a login prompt. Enter your username and password, and you’re in!