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    Openssh

    OpenSSH Cheat-Sheet

    OpenSSH is a suite of secure networking utilities based on the Secure Shell (SSH) protocol. It provides a secure way to access remote systems, transfer files, and perform various tasks.

    🔑 Known Hosts

    Remove Entry from the Known-Hosts File

    To remove an entry from your known hosts file (e.g., when a server’s key changes or you no longer need to connect to a host), run:

    ssh-keygen -R hostname

    This command removes the specified host's entry from the ~/.ssh/known_hosts file.

    ⚙️ Using the SSH Config File

    If you are regularly connecting to multiple remote systems over SSH, you can configure your remote servers in the ~/.ssh/config file. This allows for simpler and more customized SSH connections.

    Example .ssh/config File

    Host dev     
	HostName dev.your-domain     
	User xcad     
	Port 7654     
	IdentityFile ~/.ssh/targaryen.key  
	Host *     
	User root     
	Compression yes

    • Host: The alias for your SSH connection.

    • HostName: The actual hostname or IP address of the remote server.

    • User: The username to log in with.

    • Port: The port to use for the connection (default is 22).

    • IdentityFile: The path to your SSH private key for authentication.

    • Compression: Enables compression during the SSH session (optional).

    You can now connect to the dev host by simply running:

    ssh dev

    • SSH Protocol: Learn about the Secure Shell (SSH) protocol and its uses for secure communication between devices.

    • SCP (Secure Copy Protocol): A protocol to securely transfer files between hosts using SSH. Often used in conjunction with SSH for remote file management.

    • SSH Keys: Using public and private SSH keys to authenticate and establish secure connections.

    🔍 Explore More

    • OpenSSH Official Documentation: Official manual for OpenSSH with more detailed explanations of SSH commands and configuration.

    • SSH Config File Examples: Learn more advanced configurations and tips for setting up your .ssh/config file.

    • Troubleshooting SSH: A guide to solving common SSH connection issues and errors.

    🏷️ Tags

    #ssh #openssh #ssh-config #networking #remote-access #security #linux

    📚 Resources

    • OpenSSH GitHub Repository: Access the source code for OpenSSH and contribute.

    • SSH Cheat Sheet: A quick reference guide for SSH commands and configurations.

    • DigitalOcean SSH Guide: A beginner-friendly guide to SSH keys and their usage for secure logins.

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