Troubleshooting RAS Client Issues in Windows NT 4.0

This article contains steps to help you troubleshoot issues with the Remote Access Service (RAS) in Windows NT 4.0. This article focuses on issues that can occur when you use RAS to dial into another computer or an Internet service provider (ISP).

The issues discussed in this article include:

• Cannot dial with RAS
• Cannot connect after dialing with RAS

Cannot Dial with RAS

When you attempt to dial with Dial-Up Networking, the following error message may appear: If you receive this or another error message that indicates that the modem is not working properly, refer to the following articles in the Microsoft Knowledge Base: If you have upgraded from Windows NT 3.51 and you are running a program that monitors the phone line (for example, a fax program), you may receive an error message that indicates the port is busy when you try to dial out with Dial-Up Networking. For example: If you installed RAS in Windows NT 3.51 before upgrading to Windows NT 4.0, the kernel-mode telephony driver that is used in Windows NT 3.51 is retained and RAS uses non-Unimodem drivers. If another program uses the Unimodem driver and is set answer the line automatically, that program causes TAPI 2.0 to control the communications port. When this occurs, the communications port is not available to the non-Unimodem version of RAS.

To resolve this problem, remove the non-Unimodem driver and replace it with one supplied with Windows NT 4.0. To do so, follow theses steps:

1. In Control Panel, double-click Network.
2. Click the Services tab.
3. Click Remote Access Service, and then click Properties.
4. If the type of modem listed indicates that the kernel-mode TAPI driver is still being used [that is, it lists the type as "Modem (modem.inf)"], click the port, and then click Remove.
5. Click Add to add the Unimodem driver (the driver supplied with Windows NT 4.0) for this COM port.
6. Click Continue and restart your computer when prompted to do so.

Cannot Connect After Dialing with RAS

If the telephone line is unusually noisy, you may receive an error message such as: This message indicates that the modem may not be able to negotiate a connection at a higher speed. Try setting the modem speed on the client computer down to a lower speed such as 9600 bps. To do so, follow these steps:

1. In Dial-Up Networking, click the appropriate phone book entry.
2. Click More, and then click Edit Entry And Modem Properties.
3. Click the appropriate modem, and then click Configure.
4. In the Initial Speed box, click 9600, and then click the Enable Modem Compression check box to clear it.
5. Click OK.
6. Click the Server tab, click the Enable Software Compression check box to clear it, and then click OK.

If the RAS server does not answer or you cannot connect, test the connection from another computer. If you cannot connect using another computer, there may be a problem with the RAS server. Contact your network administrator for assistance.

If you can connect to the RAS server from another computer, there may be a hardware compatibility problem with your modem. Check the Windows NT Hardware Compatibility List (HCL) to see if your modem is listed. For information about where to obtain the HCL, see the following article in the Microsoft Knowledge Base: If your modem is not listed, contact the modem's manufacturer or consider trying a supported modem.