SSH tunneling (port forwarding) in Linux CLI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is SSH tunneling (port forwarding)?

SSH tunneling is a way to securely send network traffic through an encrypted SSH connection. It forwards ports from your local machine to a remote machine or vice versa, protecting data from eavesdropping.

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What is the difference between local and remote port forwarding in SSH?

Local port forwarding sends traffic from your local machine to a remote server through SSH. Remote port forwarding sends traffic from the remote server back to your local machine.

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How do you create a local SSH tunnel to forward local port 8080 to remote port 80 on example.com?

Use the command: <br>ssh -L 8080:localhost:80 [e-mail]<br>This forwards your local port 8080 to port 80 on example.com securely.

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What does the '-R' option do in SSH tunneling?

The '-R' option sets up remote port forwarding. It forwards a port from the remote server back to your local machine.

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Why is SSH tunneling useful in real life?

It helps you securely access services behind firewalls or on private networks. For example, you can safely browse a website on a remote server or access a database without exposing it publicly.

Which SSH option is used for local port forwarding?

A -R

B -L

C -X

D -D

The '-L' option forwards a local port to a remote destination.

What does remote port forwarding allow you to do?

A Forward a port from your local machine to remote

B Encrypt files on your local machine

C Create a VPN connection

D Forward a port from remote server to your local machine

Remote port forwarding sends traffic from the remote server back to your local machine.

Which command forwards your local port 3306 to remote port 3306 on server.com?

A ssh -L 3306:localhost:3306 [e-mail]

B ssh -R 3306:localhost:3306 [e-mail]

C ssh -D 3306 [e-mail]

D ssh -X [e-mail]

The '-L' option forwards local port 3306 to remote port 3306.

What is a common use case for SSH tunneling?

A Running graphical applications remotely

B Downloading files faster

C Securely accessing a database behind a firewall

D Changing your IP address

SSH tunneling helps securely access services like databases behind firewalls.

Which port does SSH use by default?

A 22

B 21

C 80

D 443

SSH uses port 22 by default.

Explain how to set up a local SSH tunnel to securely access a web server running on a remote machine.

Think about forwarding a local port to the remote web server port.

Describe the difference between local and remote port forwarding in SSH tunneling with an example for each.

Consider which side initiates the connection and which side receives forwarded traffic.