Remote Desktop Connection and RDP port forwarding

Remote Desktop Protocol: RDP is a protocol developed by Microsoft, to provide a user with a graphical interface to another computer. It is one type of application sharing protocol. In widows Xp and windows vista, RDP is pre-installed as Remote desktop connection.

Microsoft RDP includes the following features:

• Encryption
• Bandwidth reduction features
• Roaming disconnect
• Clipboard mapping
• Print redirection
• Virtual channels
• Remote control
• Network load balancing

The default port used for remote desktop protocol is port 3389. Now, if you are trying to use the Remote desktop feature of windows and are hosting your remote desktop pc from behind a router, you will require opening a port in your router for forwarding. Otherwise you can not remotely access your pc from another pc from the internet.

So what you can do is open the router configuration page. Specify another external port number and then point that port to the 3398(Default port for RDP) on the IP address of the computer that you wanted to access.

Another workaround is to change the listening port for remote desktop.

How to change the listening port for Remote Desktop

Following is the list of steps to follow to change (remote desktop protocol) RDP port:
This list includes steps that tell you to modify registry, but serious problem may occur if you do not modify registry correctly. For novice user it is better to take backup of the registry before applying following changes.

• Start Registry Editor. ( Use windows Run : type command ‘regedit’)
• Locate and then click the following registry subkey:

  HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\TerminalServer\WinStations\RDP-Tcp\PortNumber

• From the edit menu, click on the modify link and then select decimal type for value.
• You can enter here the new port number and then click OK.
• Exit the Registry Editor.

Note: After going through the above list of steps, when you try to connect to this computer by using Remote Desktop Connection, you must enter the new port.

The main reason behind changing the RDP listening port is security. Since everyone knows that 3389 is default port for RDP. So anonymous user can check that port to find if you have Remote desktop enabled and can potentially attack on your network.