Remotely Accessing A Computer

By Richard Fagen

To access a computer remotely, say calling your office computer from home, you will need to understand some new terminology.   This is because office servers behind firewalls, double network cards and high speed internet connection.  If it were simple, it wouldn’t be secure.  Once setup, it is quite simple. 

The two main terms you will need to be familiar with are:

-          “Virtual Private Network” (VPN)

-          “Remote Desktop Protocol” (RDP)

 You must establish the VPN connection before you can make the RDP call into the computer.

Intro To VPN

 A virtual private network (VPN) is the extension of a private network that encompasses links across shared or public networks like the Internet. A VPN enables you to send data between two computers across a shared or public internetwork in a manner that emulates the properties of a point-to-point private link. The act of configuring and creating a virtual private network is known as virtual private networking.

Figure 1: Virtual private network connection

VPN connections allow users working at home or on the road to connect in a secure fashion to a remote corporate server using the routing infrastructure provided by a public internetwork (such as the Internet). From the user’s perspective, the VPN connection is a point-to-point connection between the user’s computer and a corporate server. The nature of the intermediate internetwork is irrelevant to the user because it appears as if the data is being sent over a dedicated private link.

VPN technology also allows a corporation to connect to branch offices or to other companies over a public internetwork (such as the Internet), while maintaining secure communications. The VPN connection across the Internet logically operates as a wide area network (WAN) link between the sites.

In both of these cases, the secure connection across the internetwork appears to the user as a private network communication—despite the fact that this communication occurs over a public internetwork—hence the name virtual private network.

 Establishing A VPN

 To make a VPN connection you need a VPN client and a VPN server.  I won’t explain the configuration of the server component as this is very lengthy and only for administrators.  Note that I will only explain the client side for Windows 2000 Professional and Windows XP computers.  While you can access a server from a Windows 98 or NT station, it is more complicated to setup and these systems will be phased out as of June 2003.

 From the desktop, find the shortcut for “My Network Places”, right click and select properties.  This open a window called “Network and Dial-up Connections”.  Hopefully, your network administrator has already created an entry (or icon) for the computer you wish to call.  For this example, let’s call it “MyOffice”.

 Make sure you are in ‘details’ view (use menu: View, Details).  You should see the type as ‘Virtual Private Network” along with a status of “disconnected”

Note if you have a permanent or static IP address, you can skip the next part, which is setting the dynamic IP address.  (see section about obtaining a permanent IP address later in this article)

 Highlight the entry (shown above), right click and select properties.  You should see a window lie the one below.

On the General Tab, enter the dynamic address given to you by the administrator.  You shouldn’t have to change any of the other tabs.  Click Ok to close the window.

 You will be returned to the “Network and Dial-up Connections” window.  Double click the entry and you will get the login windows shown below, enter the username and password of your office’s domain

Within a few seconds, messages should quickly flash saying:

“Verifying username and password….”

“Registering your computer on the network…

 Then you should get a window like:

If you don’t want to see this message again, you can use the checkbox.  I wouldn’t recommend it as it will give you confirmation that part one has succeeded.

 Another was to confirm the VPN is to check the status in the “Network and Dial-up Connections” windows, it should now say “connected”.

 You should also notice a new icon in the system tray (lower right corner of screen, near the clock)

Moving the cursor over it should confirm the connection.

internal LAN        VPN connection

 Note, if you don’t have a home network, you will see only one of these.  Most of you will access via high speed internet so you should have a home router to protect against hacker, so you will have something similar to the above screenshot.

 Congratulations, you’ve just completed part one.

Introduction To Remote Desktop Protocol

With the Remote Desktop feature in Windows® XP Professional, you can remotely control your computer from another office, from home, or while traveling. This allows you to use the data, applications, and network resources that are on your office computer, without being in your office.

To use Remote Desktop, you need the following:

-          Windows XP Professional installed on your office computer, or whichever computer you plan to operate remotely. This computer is known as the host.

-          A remote computer running Windows 95 or a more recent version of Windows. This computer is known as the client and it must have the Remote Desktop Connection client software installed.

-          A connection to the Internet. A broadband Internet connection improves performance, but it is not necessary because Remote Desktop transfers only the minimal data (such as display data and keyboard data) to remotely control your host computer. Therefore, even low–bandwidth Internet connections allow you to remotely control your office computer.

This paper assumes that the network administrator has properly configured the host computer to allow remote users to connect to your office PC.  Make sure they also explicitly add your name to the list of authorized callers.

RDP hosting is available only with XP Pro.  Since accessing a server requires a domain, your office will have XP Pro.  You cannot setup a RDP host with XP Home.

Note that a VPN must be established first before you can attempt to make the RDP connection.  Remote users will normally VPN into the server and from there, they can RDP to any station running Windows XP Pro.

Installing Remote Desktop Connection software on a client computer

This is usually don’t by the network administrator and is done only once.  They will normally add a shortcut on your desktop for quick access.

-          Insert the Windows XP compact disc into your CD–ROM drive.

-          When the Welcome page appears, click Perform additional tasks, and then click Setup Remote Desktop Connection as shown below.

-          When the installation wizard starts, follow the directions that appear on your screen.

Getting The IP Address Of The Office Computer (optional)

This part is optional.  However, It must be done if referencing the office PC by name isn’t resolved automatically.  Your office computer is assigned its IP address (think internal phone extension) by the server.  This number is dynamic and will change periodically.  Once the VPN is established, you can access any XP Pro computer provided you know its IP address and have sufficient permissions.

One way to determine this IP address is to open a DOS box and issue a “Ping” command with a parameter equal to the station’s name.  You can open the DOS (or command prompt) from the menu by:

(Windows 2000) Start, Programs, Accessories, Command Prompt

(Windows XP) Start, Programs, Accessories… (check)

From the DOS box (black text windows shown below) enter “PING <station name>” and then hit the ENTER key.  Note, this command is not case sensitive.  This can take a few seconds to resolve the name to number translation.  In this example, I cam determining the IP address of station names “Rick”

If you are on SBS 4.5 network, the default station IP addresses will have the format 10.0.0.x (where X is between 10 and 254).  On SBS 2000 networks, the default station IP addresses will have the format 192.168.16.x (where X is between 10 and 254)

Using The RDP Client

To start the actual program, do the following:

Start, Programs, Accessories, Communications, Remote Desktop Connection

If you don’t already have a desktop shortcut, you can make one by right dragging the menu item to an empty place on the desktop and selecting “Create shortcut(s) here” from the pop-up menu.

Once started, you should see a window like the one below:

Note:  If you are having trouble resolving the name (i.e. having the computer translate the name into an actual IP address), then try and enter the office computer’s actual address as shown below.

Click on the “Options>>” control to show you more fields as shown below.

This is where you enter the computer, username, password and domain.  It is as if you were in your office.  Within a few seconds you should see your office PC’s desktop and you can work as if you were actually in your office.

Note that the computer name is the unique reference that the administrator assigns (during configuration) to each computer in your network.  The Administrator assigns the usernames (unique) and passwords to individual users.  The domain will be fixed and is assigned when the server was installed.  This value cannot be changed without reformatting the server.

There are several other values that can be set from the various other tabs.  If you are on a high speed Internet connection, then you should click on the ‘Experience” tab (shown below) and verify that you have indicated the proper speed of your internet link with the drop down list.

Getting A Permanent Or Static IP Address

Rather than manually obtaining and setting the dynamic or variable IP address, you can simplify things in one of two ways:

1)       Most likely, your company has registered a domain name.  If not, inquire with your ISP (internet service provider).  From my experience, they can be pricey and charge you from $75-100 or more a month for the service.

2)       Search the Web for ‘domain hosting’ (or something similar) and check out the various plans each company has to offer.  One that came highly recommended is a third party called DNS2GO (www.dns2go.com).  Several of myclients use it and for $50 US per year they allow you to simulate a static IP address.  It loads a small program on your PC and it simulates a permanent address.  While I haven’t personally used it, my clients simply followed the instructions on the website and did it themselves.  It must be simple, they rarely do things themselves.