Secure Shell (SSH) is a protocol that provides secure access to remote computers over an unsecured network. It provides a secure channel for communication between two untrusted hosts over an insecure network. SSH is widely used for remote administration of servers and other systems.
SSH works by encrypting all data that is transmitted between the two hosts. This includes the login credentials, commands, and any data transmitted between the two hosts. The encryption ensures that the data is protected from eavesdropping, interception, and tampering.
SSH can be used for a variety of tasks such as:
- Logging into a remote server to perform administrative tasks
- Copying files between two computers using scp (secure copy)
- Running a command on a remote server using ssh
Using SSH to Connect to a Remote Server:
The first step in using SSH is to connect to a remote server. To do this, you’ll need to know the IP address or domain name of the server, as well as your username and password. Once you have this information, you can open a terminal on your local machine and use the following command:
This command will initiate an SSH connection to the remote server with the specified username. You will be prompted to enter the password for the specified user account. Once you’ve entered the correct password, you will be logged in to the remote server.
If you’re connecting to the server for the first time, you may see a message similar to the following:
The authenticity of host 'server_ip_address (server_ip_address)' can't be established.
RSA key fingerprint is SHA256:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.
Are you sure you want to continue connecting (yes/no)?
This message is asking you to verify that you trust the remote server. The RSA key fingerprint is a unique identifier that is used to verify the identity of the remote server. If you trust the remote server, you can type “yes” to continue connecting. If you do not trust the remote server, you should type “no” and investigate the issue further.
Copying Files with SCP:
SSH also provides a secure way to copy files between two computers using the scp (secure copy) command. The syntax for scp is similar to that of the cp (copy) command:
scp source_file username@server_ip_address:/destination/path/
This command will copy the source_file to the specified destination path on the remote server. You will be prompted to enter the password for the specified user account.
Running a Command on a Remote Server:
SSH can also be used to run a command on a remote server. This is useful for performing tasks that require administrative privileges or that are easier to perform on the remote server. To run a command on a remote server, use the following command:
ssh username@server_ip_address 'command'
Replace “command” with the command you want to run on the remote server. The output of the command will be displayed in your local terminal.
SSH is an essential tool for remote system administration and secure file transfer. It provides a secure channel for communication between two untrusted hosts over an insecure network. With SSH, you can connect to a remote server, copy files between two computers, and run commands on a remote server securely