SSH (Secure Shell) is a network protocol that allows secure tunneling. SSH tunneling creates an encrypted connection between a local and remote computer to relay traffic. There are three types of SSH tunneling: local port forwarding tunnels traffic from the local machine to the remote server; remote port forwarding tunnels traffic from the remote server to the local machine; and dynamic port forwarding creates a SOCKS proxy on the local machine to transparently redirect network traffic to the remote server.

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SSH TUNNEL
</Study Day>

2. </What is SSH?>
● SSH (Secure Shell) is a Network protocol.
● Secure.
● Support cross-platform.
● NAT Friendly.

3. </How SSH work?>

4. </SSH Tunneling?>
● SSH Tunneling also called as SSH port forwarding.
● SSH tunnel is a feature of SSH.
● SSH Tunnel creates an encrypted connection between a local computer and a
remote computer through which you can relay traffic. It is very useful, and you
can use it to securely access unencrypted protocols such as VNC or firewalled
resources like database servers.
● SSH tunnel can relay traffic with IPv4 or IPv6.

5. </SSH Tunneling?>
● SSH Tunneling support:
○ Local Port Forwarding.
○ Remote Port Forwarding.
○ Dynamic SSH Port Forwarding.

6. </Local Port Forwarding?>
● SSH Local Port Forwarding is used to forward a port from the local machine to
the server machine using the SSH protocol for transport.
● Usually used to:
○ Connect to a service in the internal network from the outside.
○ Used to transfer files over the internet.

7. </Local Port Forwarding?>

8. </Local Port Forwarding?>
ssh -L 3307:192.168.1.253:3306 atb@192.168.9.2
Local Port
Port Binding on local Server Port

9. </Remote Port Forwarding?>
● SSH Remote Port Forwarding is used to forward a port from the server machine
to the local machine using the SSH protocol for transport.
● Usually used to:
○ Expose local to the internet.
○ Explore the resources which are behind the firewall.
○ System administrators and IT professionals use it for opening backdoors into the
internal network from their home machines.
Need enable GatewayPorts on ssd_config

10. </Remote Port Forwarding?>

11. </Remote Port Forwarding?>
ssh -R 3100:localhost:80 atb@192.168.9.2
Remote Forward
Server Port local Port

12. </Dynamic Port Forwarding?>
● Make remote resource accessible on your local machine.
● It created SOCK proxy in local machine.
● All client application(browser) are configured to SOCKS proxy setting.
● What are the contents sent to that port is transparently redirected, encrypted
to remote server.
● Response from remote machine is received in same way.

13. </Dynamic Port Forwarding?>

14. </Dynamic Port Forwarding?>
ssh -D 9001 atb@192.168.9.2
Dynamic Forward
Local Port

15. </Demo>
● Local Port Forward MySQL Port 3306.
● Remote Port Forward HTTP Port 80
● SOCK proxy.

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