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SSH (Secure Shell)

SSH is used for secure remote login and other network services between two networked computers.

Client Commands​

Connect to a Remote Server​

ssh <user>@<hostname_or_ip>

Example: ssh <username>@192.168.1.5

Connect with a Specific Key​

ssh -i <path_to_private_key> <user>@<host>

Server Configuration (/etc/ssh/sshd_config)​

Common configuration tasks on the server side. After changing config, always restart the service: Restart SSH (sudo systemctl restart sshd)

Important Settings​

  • PermitRootLogin: no (Disables direct root login for security)
  • PasswordAuthentication: no (Requires SSH keys, disables password login)
  • PubkeyAuthentication: yes (Enables SSH key authentication)
  • UsePAM: yes

Managing Authorized Keys​

To allow a user to connect, add their public key to ~/.ssh/authorized_keys.

nano ~/.ssh/authorized_keys
# Paste the public key, save, and exit.
chmod 600 ~/.ssh/authorized_keys