With the surge in popularity of the Internet, Remote Access Service (RAS) and its counterpart, Dial-Up Networking (DUN), have become more complicated and more commonly used. In this article, I'll look at RAS not as a gateway to the Internet but as it was originally designed, for dialing in to a computer and accessing resources on that computer or on a corporate network.
What RAS Does
RAS lets a user dial in to a network and use the dial-in connection exactly as if it were a network connection. Of course, that connection is slower than a regular network connection, but in many situations, it provides enough capability to transfer files and email. The key to understanding RAS is knowing that it is just an extension of your network.
Once connected, RAS is a communications channel. It does not do anything for you--if you want to connect to a drive on the network, you must follow the usual procedures: From your remote computer, use Windows NT 4.0's My Computer icon with the Map Network Drive option, or explore the network through the Network Neighborhood icon, just as if you were at your computer in the office. In NT 3.51, use File Manager to connect to a shared drive or directory on the network.
Remote Access, Not Remote Control
RAS is not a remote control program. You connect to the host computer just like any other network connection, such as your Ethernet or Token-Ring network connection at the office. You access network resources from your remote computer in the same way. If you want to run a program that is on the host computer, download and run the executable code on your remote computer.
If you are looking for remote control software, consider one of the many third-party packages such as Symantec's pcANYWHERE or Avalan's Remotely Possible/32. (For product reviews, see John Enck, "Symantec's pcANYWHERE32," and "Avalan's Remotely Possible/32," May 1996.) These programs run an application on the host computer, duplicate the host computer's screen display on your screen, and accept mouse and keyboard input from your computer.
RAS is also not a file synchronization program of the Laplink variety. To emulate a synchronization package, connect with RAS and compare host and remote directories, either manually or with software designed for that task. But to keep two computers synchronized, RAS is not the complete answer.
Where to Use RAS
RAS's primary function is to let you access files on a server from a remote location. Suppose you are working on the budget forecast and you want to work from home in the evening. You can take home the files you need--perhaps move them to a laptop computer or use a ZIP drive. But that approach requires that you know in advance all the files you will need.
And let's say a coworker is revising some estimates but will not be finished with them until 7 pm. Are you going to wait at the office or have your colleague email the files? If the files are on the server, you can use a RAS connection and pick them up later. With the Excel 97 cooperative technology, the two of you can work on the same file at the same time. RAS is great for people who travel and need to exchange files with the computer at the office or connect to a corporate database through a dial-in connection.
A RAS server is the host machine through which you connect to the target resources. Any computer running NT can act as a RAS server. An NT Workstation computer can act as a RAS server, but it can support only one inbound connection. The intent is to let users dial from home to their office computer and access the files on that computer. In contrast, an NT Server computer, can act like a true RAS server, supporting up to 256 incoming connections. (To achieve that number, you must install specialized hardware, such as a Digiboard.)
Setting Up RAS
I'll explain the NT 4.0 setup, but the NT 3.51 setup is similar. From Control Panel, open Network. Select the Services tab, and click Add. Then select Remote Access Service from the list you see in Screen 1, and click OK. The system will prompt you for the location of the NT installation files (most likely your CD-ROM or a network share).
If you have not installed a modem, you must do so now. The RAS setup uses the standard modem installation dialog boxes. Select your modem, and when you get to the Add RAS Device dialog box shown in Screen 2, click OK. If you've already configured your modem, you'll skip the modem setup steps and go directly to the Add RAS Device dialog box.
Now that your modem is set up for RAS, you must attend to a few more items. Continue with the installation to get to the Remote Access Setup dialog box shown in Screen 3.
Two items here require attention. The Configure button pops up the dialog box shown in Screen 4, where you can specify whether to use this port to dial out, receive calls, or both. The Network button in the Remote Access Setup dialog box lets you specify which network protocols to use for outgoing and incoming calls. From here, you can configure your network parameters, including whether to use Dynamic Host Configuration Protocol (DHCP) to assign IP addresses. (For more information about DHCP, see John Enck, "Take a Number," October 1995, and Mark Minasi, "DHCP and Assigning IP addresses," August 1996.)