PC Hell: How to Use Remote Desktop to Access Multiple Computers on LAN

What are Ports and How Do They Work?

Computers have different ports that are assigned specific numbers. These ports allow information into and out of the computer. For instance, port 80 is used by the web, while port 23 is used by FTP programs. Firewalls block information from accessing the ports on a computer unless the firewall is specifically told to allow something through. For this reason, we need to be able to setup each remotely accessed computer with a separate port and tell the firewall which computer is using each port.

Remote Desktop Ports

Windows Remote Desktop uses port 3389 to send and receive data. So the first computer being accessed remotely will be assigned this port to use for Remote Desktop. While the other computers in the local area network will be assigned sequential numbers starting with 3390. So, the second computer would be given port 3390, the third would use port 3391 and so on.

Follow the directions below to change the listening port for Remote Desktop and each computer you wish to access remotely.

1) Click on Start, Run
2) Type REGEDIT and press Enter
3) Click on the plus signs (+) next to the following sections in the Registry Editor

HKEY_LOCAL_MACHINE
System
CurrentControlSet
Control
TerminalServer
WinStations
RDP-TCP

4) In the right-hand column find the section called PortNumber
5) Double-click on the name PortNumber
6) Choose the Decimal option under Base and type the correct port number using the information above.
7) Click OK
8) Close the Registry Editor
9) Repeat this procedure on each computer you wish to access remotely along with the steps involved in setting each computer up to use Remote Desktop.

Changing the Firewall to Allow Access

Now that each computer is assigned a unique port to use for Remote Desktop, you'll have to tell the firewall running on each computer to allow that port through. Follow these steps to change the Windows Firewall to allow access.

1) In the Control Panel, click on the option for Security Center
2) Click on Windows Firewall under the heading "Manage Security Settings For"
3) Verify Windows Firewall is turned on
4) Click on the Exceptions tab
5) Click on the Add Port button
6) In the Name field, type REMOTE DESKTOP 2
7) In the Port field, type the port you assigned to the computer in the previous section: 3389, 3390, etc.
8) Choose TCP as the protocol and Click OK
9) Verify that there is a checkmark for the option REMOTE DESKTOP 2 and Click OK

Changing Your Router to Allow Access

Lastly, you'll need to make a change in your router for each computer you want to access. This change is called Port Forwarding and a friend of mine has created a great site called PortForward.com to explain how to do this. Depending on your router the procedure is slightly different, however there are great tutorials on portforward.com to explain this.

Each computer you want to access must have its own static ip address on your network. There are two steps involved in setting a static IP address for each computer: discover your current ip address and assign the current ip address to your computer.

Discover the Current IP Address on your computer

1) Click on Start, Run
2) Type CMD and press Enter
3) At the blinking cursor, type IPCONFIG /ALL and press Enter (remember there is a space between IPCONFIG and /ALL)
4) Find the section for the Connected Ethernet Adapter and write down the following information

IP Address
Subnet Mask
Default Gateway
DNS Servers

5) Type EXIT and press Enter to close the window

Assign the Current IP Address to Your Computer as a Static IP

1) Click on Start, Control Panel
2) In Classic View: Open Network Connections
In Category View: Select Network and Internet Connections, then click on Network Connections
3) Right-click on your active LAN or Internet connection
4) Click on Properties
5) In the General tab, highlight Internet Protocol (TCP/IP) and click Properties
6) Under the General tab, click Use the following IP Address and enter the information you wrote down in the previous section for this computer including

IP address
Subnet mask
Default gateway

7) Click the option for Use the following DNS server addresses and enter the DNS servers your router is using
8) Click OK and then click OK again to leave the Network Settings section
9) Restart your computer
10) Follow the procedure above to check your current IP address and verify its the same as before
11) Finally, test the connection and make sure you can access the Internet.
Port Forward the Remote Desktop Port

Now you are ready to modify your router to port forward the remote desktop port number to the correct computer. Use the tutorials on PortForward.com to make changes to your router. Although the specific information will be different for your situation, you'll forward the port you assigned for Remote Desktop to the static IP address you assigned for that particular computer. If you have three computers you are trying to reach with Remote Desktop, then you'll have three entries in the port forward section of your router to accomplish this.

Also, its best if your internet connection to your LAN is assigned a static IP by your ISP. If you dont have a static IP, you will find it harder to connect because your IP will change each time your router is rebooted. To discover your current LAN IP, go to the website WhatIsMyIP.COM and it will show you your current IP.

As an alternative, you can sign up for a free Dynamic DNS account to track your IP and be able to access your network. You can sign up for DynDNS by visiting their site at http://www.dyndns.com

Using the Remote Desktop Connection to Connect to Each Computer

Now, you can test the remote desktop connections from another location.

1) On your laptop or another computer not connected to your LAN, open the Remote Desktop Connection software under Accessories and Communications
2) On the Remote Desktop screen type the IP of the network you want to connect to followed by a colon and the port number you wish to connect to.

Example: 215.76.43.5:3390

3) Finally click connect and see if you can reach your computer. If the connection is successful, you will be presented with the login screen for your computer, type your username and password and click Ok to access your computer.
4) Test this connection for each computer you wish to connect to behind your local area network.

NOTE: You'll have to log into an account on your computer has been assigned a password. If you don't have a password assigned, you'll need to assign one before using Remote Desktop to connect.

How to Backup and Restore Outlook Express Mail, Address Book, Blocked Senders List and other Settings