Linux for Developers Course
Linux for Developers
/
Beginner

SSH (Secure Shell)

Definition

A cryptographic network protocol used for operating network services securely over an unsecured network. It provides a secure channel to log into a remote computer and execute commands.

Explain Like I'm New

Teleporting into another computer. It lets you open a terminal window on your laptop, but everything you type actually executes on a server thousands of miles away, and hackers can't intercept the data.

Real World Example

An AWS server is running in Virginia. A developer in London types `ssh admin@198.51.100.14`. They are instantly connected and can run commands on the Virginia server as if they were sitting in front of it.

Common Use Cases

  • •Remote server administration
  • •Secure file transfers (SCP)

Interview Questions

basic

  • What port number does the SSH protocol run on by default?

intermediate

  • Why is it a major security risk to leave SSH accessible via a simple password instead of an SSH Key?

Flash Cards

Question

Default port?

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Answer

Port 22.

Question

Why is password risky?

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Answer

Because thousands of automated hacker bots constantly scan the internet for servers with Port 22 open, running 'brute force' attacks guessing thousands of common passwords a second until they break in.