Secure shell (SSH) is a protocol that facilitates secure communications between two systems using a client/server architecture and allows users to connect to a host remotely. Unlike other remote communication protocols, such as FTP or Telnet, SSH encrypts the connection session, making it impossible for anyone to obtain unencrypted passwords.
SSH is a protocol that was built with the aim of offering a secure alternative to other commands for remote connection from another machine, and allows you to authenticate a user through a secure channel.
For Mac and Linux users, the ssh command comes installed by default. The SSH command consists of three different parts:
ssh {user}@{host}
The following are the three different parts of a SSH command:
- The ssh key command tells your system that you want to open a secure and encrypted shell connection.
- {user} represents the account you wish to access. For example, you can use the root user to authenticate with full permissions on the server.
- {host} refers to the server IP address or domain you need to access.
When you press Enter, you will be asked to enter the password for the requested account. When you write it, nothing will appear on the screen, but your password, in fact, is being transmitted. Once you have finished typing the password, press the Enter key again, even though you will not see the password you introduced in the console. If your password is correct, you will receive a remote Terminal window.
This is the output you will receive when you try to connect with the 192.168.0.1 IP address using the ssh root@192.168.0.1 command:
The authenticity of host '192.168.0.1 (192.168.0.1 )' can't be established.
ECDSA key fingerprint is SHA256:NW6uvRVer4uKQAQt+USwpeFwjz0NDqvflzbwM9c5SR4.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.0.1 ' (ECDSA) to the list of known hosts.
root@192.168.0.1 's password:
Last login: Fri Mar 8 14:31:58 2019 from 192.168.0.1