PuTTY is an excellent network utility. It is a free open source telnet/ssh client that is extremely versatile. It offers a GUI environment that is easy to navigate with loads of options such as port forwarding. With port forwarding I have also found a great tool in Putty, in that I can use to act like a SOCKS5 proxy server. This is truly useful especially when connecting to a unsecured wireless hot-spot such as in a coffee shop. What better way to encrypt you connection than using SSH with a SOCKS5 proxy server. The setup is quite simple really. Just put in your normal session information like your host name/IP address with your SSH port number generally 22. Then you going to want to go to “Connection-SSH-Tunnels” Here you just have to put some random port number in the source port, lets say 5555. Then click the dynamic radio button and then click add.
Then click open to open the connection and when prompted input your user name and password to the box you have setup for SSH. Once that is done all you need to do is input the proxy information into your web browser or IM client, or whatever you have connecting to the internet that you want to be encrypted. Just simply open up the connection properties of you web browser for instance and put in the proxy server as “localhost” and the port number as whatever you chose as that dynamic port in this case “5555.” And viola you now have a secured, encrypted web browser environment even though you are on an unsecured wireless network. Again this just shows how useful and versatile Putty is.
Of course you can still do traditional port forwarding. One useful port forwarding technique is to get onto you home machine no mater were you are, no mater if you are behind a firewall or not. generally everywhere you go port 22 for SSH will be open as it is commonly used to manage servers and such. So it is very unlikely that this port will be blocked. You could also setup you SSH sever to listen on the https port (443) as well which is guaranteed never to be blocked. So you will use putty to SSH into you box but with certain port forwarding parameters set. For this example I will consider Windows XP using a default RDP connection. Once we have all of our session info in for Putty we will go to “Connection-SSH-Tunnels” again. Here in the source port put in some random port again but NOT 3389, as this is the standard RDP port. Then in the destination box put in the local IP address of the machine you wish to RDP into, the colon and the port number 3389. Make sure that the Local radio button is active in this case Much like the example below. Then click add, and then open to open your SSH connection.
The run “mstsc” by using the “Start-Run” command or just open remote desktop from the all programs menu in Windows XP. When inputting the computer you want to connect to simply put in “localhost” colon and then the random port number you chose, in this case 4444. So the computer you want to connect to box would look like “localhost:4444″ Then just click connect and away you go, remote desktop-ing to your computer from anywhere, and best of all its on an encrypted tunnel.
For more information on PuTTY and other various tools they have such as pagent and pscp visit http://www.chiark.greenend.org.uk/~sgtatham/putty/
more to come on other tools from that site as well.
