SSH configuration files

SSH client configuration file

This file is usually located at:

• Linux/Unix: /etc/ssh/ssh_config (system-wide) or ~/.ssh/config (user-specific)
• Windows: C:\ProgramData\ssh\ssh_config

Common Directives:

• Host: Specifies a pattern for matching host names.
• User: Sets the username for the SSH connection.
• Port: Specifies the port number to connect to on the remote host.
• IdentityFile: Specifies the file from which the user's private key is read.

Sample ssh_config

# Default SSH options
Host how_i_would_identify_the_server
    User your_username
    Port 22
    IdentityFile ~/.ssh/id_rsa

SSH daemon configuration file

This file is usually located at:

• Linux/Unix: /etc/ssh/sshd_config
• Windows: C:\ProgramData\ssh\sshd_config

Common Directives:

• Port: Specifies the port number for the SSH daemon.
• ListenAddress: Sets the IP addresses that the SSH server listens on.
• PermitRootLogin: Controls whether the root user can log in directly.
• PasswordAuthentication: Enables or disables password authentication.
• PubkeyAuthentication: Enables or disables public key authentication.
• AllowUsers: Restricts which users can log in.

Sample sshd_config

# Port to listen on
Port 22

# Allow root login
PermitRootLogin no

# Use public key authentication
PubkeyAuthentication yes

# Allow specific users
AllowUsers user1 user2