📖 What is SSH?
Secure Shell (SSH) is a cryptographic network protocol providing secure remote access to a computer. It encrypts all communication, protecting against eavesdropping and man-in-the-middle attacks, and is commonly used for remote command-line access and secure file transfer.
"SSH operates on TCP port 22 and is a secure replacement for Telnet. Understand the use of SSH keys for authentication, which enhance security over password-based logins. Exam questions may involve identifying SSH’s security benefits and configuration options."
📚 Certification: CompTIA A+ Certification Exam Core 2 (220-1102)
🔑 What are the Key Concepts of SSH?
- ▸ SSH uses cryptographic keys to verify the identity of both the client and server, providing strong authentication.
- ▸ Password-based SSH authentication is less secure than key-based authentication and should be disabled when possible.
- ▸ SSH can be used for secure file transfer via SCP and SFTP, providing encrypted alternatives to FTP.
- ▸ Port forwarding with SSH creates secure tunnels for other network services, enhancing overall security.
- ▸ SSH configuration files (like sshd_config) control server settings, including allowed users, ports, and authentication methods.
🎯 How does SSH appear on the 220-1102 Exam?
You may be asked to identify the protocol used to securely administer a remote Linux server from a Windows workstation.
A scenario might describe a security audit revealing a system still using Telnet; determine the recommended replacement protocol.
Expect questions about troubleshooting failed SSH connections, including checking firewall rules and authentication methods.
❓ Frequently Asked Questions
What is the benefit of using SSH keys over passwords?
SSH keys are significantly more secure than passwords because they are much harder to crack through brute-force attacks. They also prevent password sniffing.
How can I improve SSH security beyond just using keys?
Disable password authentication, change the default SSH port (22), use a firewall to restrict access, and regularly update the SSH server software.
What is SSH tunneling used for, and why is it important?
SSH tunneling creates an encrypted connection that can forward other network traffic. This is important for securing insecure protocols or accessing resources behind firewalls.