Remote Desktop and Remote Assistance - by Andrew, Dan and Anne Delong

Correction: For those who attended the computer club presentation: Dragging and dropping of files between computers, during a Remote Desktop session, works! -- As does copy/pasting. (How to do so is explained in the Conclusions at the end of this article.) For full, illustrated, instructions refer to the complete PowerPoint presentation (right here, below) at:

Remote Desktop Powerpoint presentation as an Adobe PDF file (1.68 MB)

Remote Desktop Powerpoint presentation as an IE Web page (works only with Internet Explorer 5 or better)

The purpose of this talk was to demonstrate the built-in capabilities of any Windows machine (the Client), to take over the desktop of a remote machine (the Host), and to do so unattended.

Remote Assistance (is not Remote Desktop)
The simplest way to take over another person’s desktop is by activating Windows Remote Assistance [which is not the same as Remote Desktop]. Anne showed how she could send an invitation to Dan (by way of Windows Messenger, or Outlook or as an e-mail file attachment), with our without a password. Dan then opened the invitation, typed the password in order to respond to her request. Anne clicked YES to this response. Dan was then able to see (on his screen) all of Anne’s actions. The two users could type messages (chat); they could both start a voice conversation; and they could both send files. A menu choice on Dan’s screen allowed him to request taking total control of Anne’s desktop. When selected, Anne, once again, had to give permission for this to occur. She could break the connection at any time. This kind of remote desktop connection is limited to 24 hours.

Remote Desktop
Remote Desktop required much more time to fully explain. This feature of Windows XP lets one or more user access the remote computer, just the same as they would if sitting at the computer itself, using its keyboard and mouse. The user gains access to all files and programs, perhaps from a different room, or from an Internet connection across the globe. The remote computer does not need to be supervised by a human operator, nor is the length of connection time limited (once this host computer has been configured to accept remote connections). Amongst the reasons large and small companies use remote computing:

  • Many client computers may connect to the host computer at the same time
  • Any application that is installed on the host computer is available to the client (i.e.; no need to install the application on the client computer. This saves a lot of money in software licensing.)
  • The host, or remote computer, may be left unattended.

The following three scenarios, for setting up Remote Desktop, were shown (ranging from a simple LAN configuration to a more complex Internet connection):

1. Behind the firewall, or inside the LAN (local area network): This Remote Desktop configuration is fairly easy to accomplish (if all of the computers involved are on the same local area network, or LAN). Each computer is recognized on the network by its unique name. The connection should work as long as a firewall does not object. Note: Usually the LAN’s router is the firewall – as in an office setting and in many homes. Or, it could be a software firewall, like Zone Alarm or Windows Firewall. On a LAN, Remote Desktop just needs to know the unique name of the computer that has been set up as the host computer. Also, the host computer must have its Remote Desktop service turned on. In addition, it must be running Windows XP Pro or Vista (Ultimate, Enterprise or Business), or a “Longhorn” server. Just type the name of the host computer (e.g.; mymainPC) into the remote desktop login field and – presto! – You have control of the host computer’s desktop. (A security requirement for all Remote Desktop logins is that the host computer must have been given a user login, with password).

2. Beyond the Firewall, outside the LAN, or on the Internet: This configuration requires knowledge of two IP addresses and a method for by-passing the firewall. Since most people use a firewall to protect from incoming snooping, some tweaking is required to permit Remote Desktop to ‘snoop’. In Windows Firewall (if active), adding Remote Desktop to the list of exceptions will prevent further blocking of Remote Desktop. If a router (e.g.; DLink or LinkSys) supplies the firewall to the LAN, then some form of port forwarding must be implemented, such that Remote Desktop is given exclusive use of a port (3389 by default) that is forwarded to the internal IP address of the host computer (e.g.; The user must also find the external Internet IP address of the router (also knows as WAN address – e.g.; The WAN address is then entered into the remote desktop login field instead of the unique computer name, as was done in scenario 1. above. (The unique computer name method only works inside a LAN configuration.) Find the WAN address of the host computer from a site like

3. Beyond the Firewall, on the Internet, when the Internet IP is not static: This method overcomes the problem of randomly changing IP addresses. Most Internet Service Providers do not leave the Internet IP address, or WAN address, of the high speed modem the same for very long (unless you pay the ISP to keep a static IP address on your DSL modem/router). Note: The only way to reliably use scenario 2. above is to check the current Internet IP address of the host’s router just before every remote connection. This requires someone to be at the host computer to do the IP address checking, and to communicate that IP to the user at the client computer. To overcome this dynamic IP address problem, an Internet service – DynDNS –keeps track of such changes for you, and they will give you a special host name that never changes. It works as a DNS alias for your external Internet IP address. DynDNS updates the linkage between your changed IP address and this special host name. From this point on, you no longer need to know the Internet IP address, or WAN address, of your router; you use this special host name in the remote desktop login screen instead (e.g.;

It is important to mention that, just like the dynamic IP address given to the DSL modem/router by you ISP, each computer connected on a LAN may also be given a unique LAN IP addresses by the router. The router ‘dishes out’, or serves, IP addresses as needed each time a new computer is hooked up to the LAN, and sometimes when a computer is moved to a different port on the router. This doesn’t happen often, but just to be sure that port forwarding (mentioned in Step 2) doesn’t have to be updated, many users assign a unique static IP address to each computer on the LAN.

Alex, our newsletter editor, advocated the use of CrossLoop, (mentioned in the FYI section of the April 2007 edition of Monitor). CrossLoop is a free program for sharing desktops, which now includes file sharing. (Quote from April 2007 below)

Share your desktop (as the host computer) over the Internet with CrossLoop, an easy to configure, and easy to use, remote access application. The transmission of data between host and guest computers is 128 bit Blowfish encrypted, with access key-protection for even stronger security. Both computers must install the program. The host computer (the Server) generates a 12-digit key, which must be e-mailed, or phoned, or instant messaged to the other user (the Joiner), who will then be granted access to your desktop. The interface is designed for ease of use by non-technical users, and will work through firewalls and router NAT (Network Address Translation)... /

Like XP’s Remote Assistance, CrossLoop requires user input (a person) at each end of the connection, which is unlike XP’s Remote Desktop because it does not require user input from the host computer. However, Remote Desktop requires the host computer to be XP Pro, Vista (Ultimate, Enterprise or Business), or a “Longhorn”.

Conclusion: Configuring a XP or a Vista Remote Desktop host machine is fairly simple when working within a LAN (local area network), where only the name of the client machine needs to be entered into the remote connection login field. Accessing a host computer from the Web (outside the LAN) requires more work. Once configured, Remote Desktop allows many simultaneous connections.

And, it does allow dragging and dropping of files between machines (as long as the remote desktop is being viewed full screen and not in a window). Here’s how. When first entering the connection details in the client login window, and before clicking OK, click on Options … Local Resources and select the check box that shares the disk drives. Now, when you click on the remote computer’s My Computer, you will see additional hard drives added to the list. They are the hard drives on the client computer. Just open separate copies of Windows Explorer for drives on the client and the host, and drag and drop between those windows.

posted August 16, 2007