How to Create an SSH Tunnel With Putty

SSH tunnels are encrypted pathways that allow users to bypass firewalls that prohibit certain Internet traffic. This guide will help you create an SSH tunnel with Putty, a free software client. In this example we will be connecting to the computer at 201.31.56.23 (port 80) through the server at 203.102.79.2 (port 22), using the local port of 8088.

Difficulty: Moderately Challenging

Instructions

1. Launch Putty by double-clicking the Putty icon or opening it through the Start menu.

2. Click "Session." Here you will enter the details of the forwarding server you are connecting to.

3. Enter the address of the server that is running SSH in the Host Name field and the port number in the Port field. In our example, the address is 203.102.79.2 and the port is 22.

4. Select "SSH." Click "Connection" in the left pane, then "SSH," then "Tunnels." Here you will enter the information regarding the computer you are ultimately connecting to.

5. Enter the port number you wish to use as the local port into the Source Port field. This is the port that you will connect to using the program you wish to tunnel with, and cannot be in use by any other application. In our example this port is 8088.

6. Enter the address of the computer you wish to ultimately connect to followed by a colon and the port number into the Destination text field. In our example, this is 201.31.56.23:80.

7. Select "Local," then click "Add."

8. Click "Open" to begin your SSH session. You will be prompted for your username and password.

Tips & Warnings

• You can save your settings in the Session section of Putty so that you can do this all over again without re-entering all the information.
• There are many applications for SSH tunnelling, including accessing a remote Web server through a firewall and securely downloading your email through an insecure network.
• Make sure you have all your ports sorted out for all the servers involved or this process won’t work.
• Don’t use a port that is in use by any other application for your Source Port. Commonly used ports are 21, 25, 80 and 110. Consult a more comprehensive list of standard ports if you experience problems.