Mastering Secure Shell (SSH)

Understand that the secure shell (ssh) is a protocol for encrypted remote connections, enabling authentication, encryption, and integrity. Recognize OpenSSH as a common open-source implementation.

Trace the history of the secure shell, noting its open source release in 1995, the Internet Engineering Task Force's involvement, and how the SSH protocol replaced Telnet and FTB.

Learn how to ssh from a Windows machine into a Linux host using PuTTY, create a connection profile, handle the first-time fingerprint prompt, and log in with credentials.

Understand the public and private key concept and the basics of key pairs, then generate the keys on Linux and Mac systems and use them.

Learn how to set up ssh keys and enable passwordless access by generating key pairs on Linux and Mac, then copying public keys to target servers.

Generate a public and private key pair on a Linux machine, then copy the public key to the remote machine’s authorized_keys and connect via ssh without a password.

Generate a public and private key pair on Windows, save them, copy the public key to the Linux machine's authorized_keys, and configure the client to use the private key.

Install and start the OpenSSH server on CentOS using yum, verify port 22 is listening, and SSH from another Linux machine after restarting the service.

Install and start the OpenSSH server on an Ubuntu VM, verify status, and connect from a second VM to complete a basic SSH setup.

Learn to ssh to a server behind a jump box by first logging into the jump server, then ssh into the target on the nat network from the bridge network.

Master local forwarding with ssh by mapping a client's local port to a remote server port through a jump box, enabling access to web services via ports 80 and 22.

Enable X11 forwarding in SSH to display Linux GUI apps on a Windows machine, demonstrated by accessing Fedora GUI tools like disk manager and Firefox via an X11 server.

Explore ssh related files, including system wide and user specific configurations, keys, and known_hosts. Understand key based authentication and host identity verification from sshd_config to authorized_keys.