Remote access

server represents the server's hostname, domain name, or IP address.

telnet

Telnet is the traditional protocol for making remote console connections over TCP.

The telnet daemon running on a server listens for telnet connections on TCP port 23.

Installation (Ubuntu)

sudo apt install telnetd

Verify daemon is active

sudo systemctl enable --now telnetd

Now, we can access the server through a client terminal.

telnet server

Telnet traffic is easily sniffed for passwords and connections should never be made over any untrusted network.

Secure Shell (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network.

Installation (Ubuntu)

sudo apt install openssh-server

Verify the daemon is active

sudo systemctl enable --now ssh

Now, we can access the server securely through a client terminal.

ssh user@server

If connecting to a foreign host for the first time, you must accept the ECDSA key fingerprint by typing yes.

SSH has many advanced configuration options. Eg. SSH default port is 22, changing this to something unpredictable is recommended.