📖 What is Secure Shell (SSH)?
Secure Shell (SSH) is a cryptographic network protocol used for operating network services securely over an unsecured network. It is most commonly used for remote command-line login and remote command execution, providing strong encryption for the session.
"SSH typically operates on port 22. It is the secure alternative to Telnet, which sends data in plain text."
📚 Certification: CompTIA A+ Certification Exam Core 1 (220-1101)
🔑 What are the Key Concepts of Secure Shell (SSH)?
- ▸ Operates on TCP port 22, which must be open on the target device's firewall to allow remote administrative access.
- ▸ Provides strong encryption for all transmitted data, protecting sensitive credentials and commands from being captured by packet sniffers on the network.
- ▸ Serves as the secure replacement for Telnet, eliminating the risk of plaintext communication during remote management of network devices.
- ▸ Supports multiple authentication methods, including standard password-based logins and more secure public-key authentication using cryptographic key pairs.
- ▸ Commonly used by system administrators to manage Linux servers, network switches, and routers via a secure command-line interface.
🎯 How does Secure Shell (SSH) appear on the 220-1101 Exam?
You may be asked to identify the most secure protocol for a technician to use when remotely configuring a core switch from a different subnet.
A scenario might describe a security audit finding that administrative traffic is being sent in cleartext; you must recommend replacing Telnet with SSH.
Expect questions where you must identify port 22 as the default port associated with secure remote command-line access in a troubleshooting context.
❓ Frequently Asked Questions
Can SSH be used for more than just command-line access?
Yes, SSH is the underlying transport for SFTP (Secure File Transfer Protocol), allowing for encrypted file uploads and downloads, and can also be used for secure port forwarding.
What happens if the SSH port is changed from 22 to something else?
Changing the default port is a common security practice to reduce automated bot attacks, but the technician must specify the custom port when initiating the connection.