Alternate Port for RDP

This is going to be short and sweet!

Often, smaller networks use RDP as their primary method of remote administration. This is really great if you are using one of Microsoft’s SBS servers because the Remote Web Workplace wizard will automatically add all clients and allow easy access through a website harnessing the power of TSWEB.

But what if you just have a few machines behind a firewall and would like to be able to RDP into all of them? The answer is simple – change the port that RDP listens on on the client OS.

RDP by default listens on 3389. I find 3390 and 3391 are always good alternate choices that are almost never used by any other applications. You can use any port you like if it is free, however.

Simply open regedit32 (this is accomplished by typing regedit on the command prompt or in the run box).

Migrate to the following key:

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

On the Edit menu, click Modify, click Decimal, type the new port number, and
then click OK.

Exit out of the registry editor.

Now, go ahead and forward your firewall to pass that port through to the IP address of the client you have modified.   (Note:often routers will enable you to port forward external ports to different internal ports – this is equally effective and means that these registry changes would be unnecessary. There are many reasons for changing ports – use your best judgement)

Test it by using telnet.

For example: telnet mail.examplecompany.com:3391

You will know if it has connected if your cursor just starts blinking in a blank window and doesn’t display any error message.

Now, when you want to connect, use your RDP client and append your new port number to the address like below.

It’s that simple.  I know a lot of you out there will find this extraordinarily useful…and oh yeah, by the way…standard disclaimer applies when working with the registry: back it up first, we bear no responsibility in you making a mess of it.

Cheers….