Troubleshooting Internet Service Provider Logon Problems

This article was previously published under Q161986
This article has been archived. It is offered "as is" and will no longer be updated.
For a Microsoft Windows XP version of this article, see 314455.
SUMMARY
This article describes how to troubleshoot Internet service provider (ISP)logon problems. This article discusses only logon problems, not modem ordialing problems. For information about modem or dialing problems, see thefollowing articles in the Microsoft Knowledge Base:
ARTICLE-ID: 161516
TITLE : Troubleshooting Modem Problems Under Windows NT 4.0

ARTICLE-ID: 162293
TITLE : Troubleshooting RAS Client Issues in Windows NT 4.0
MORE INFORMATION
When you attempt to connect to your ISP, you may receive one of thefollowing error messages:
Error 629: The port was disconnected by the remote machine.
Error 640: A NetBIOS error has occurred.
You may experience problems connecting to your ISP for any of thefollowing reasons:
  • The settings for your dial-up connection to your ISP are configured incorrectly.
  • Your ISP's Point-to-Point protocol (PPP) server is not functioning properly.
To determine and resolve the problem you are experiencing, follow theprocedures in each of the following sections in order. After you finisheach procedure, check to see if you can connect to your ISP successfully.

Verify Your Username and Password

Make sure that Caps Lock is not accidentally on, and then verify that youare typing your username and password exactly as provided by your ISP. Ifyou are not sure what your username and password are, contact your ISP forassistance.

Accept Any Authentication Including Clear Text

Configure your dial-up connection to your ISP to accept anyauthentication, including clear text. To do so, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click the Security tab, click Accept any authentication including clear text, and then click OK.

Lower the Connection Speed

If phone line noise or other interference is a problem, lowering yourconnection speed may allow you to connect to your ISP. To lower yourconnection speed, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click your modem in the Dial Using box, and then click Configure.
  5. In the Initial Speed (BPS) box, click 9600, and then click OK.
  6. Click OK.
If you are able to connect at a lower speed, or if phone line noise issuch that you cannot connect, have the phone company check the phonelines.

Disable Hardware Flow Control

Disable Hardware Flow Control in your dial-up connection to your ISP. Todo so, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click the Basic tab, click Configure, click the Enable Hardware Flow Control check box to clear it, and then click OK.
  5. Click OK.

Disable Modem Error Control

Disable Modem Error Control in your dial-up connection to your ISP. To doso, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click the Basic tab, click Configure, click the Enable Modem Error Control check box to clear it, and then click OK.
  5. Click OK.

Disable Modem Compression

Disable Modem Compression in your dial-up connection to your ISP. To doso, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click the Basic tab, click Configure, click the Enable Modem Compression check box to clear it, and then click OK.
  5. Click OK.

Disable Software Compression

Disable Software Compression in your dial-up connection to your ISP. To doso, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click the Server tab, click the Enable Software Compression check box to clear it, and then click OK.

Disable LCP Extensions

You may have trouble connecting to your ISP if your ISP's Point-to-Pointprotocol (PPP) server does not support Link Control Protocol (LCP)extensions. LCP extensions include a Callback option, Time Remaining, andIdentification packets as defined in RFC 1570. Contact your ISP todetermine whether you should disable LCP extensions.

To disable LCP extension, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click the Server tab, click the Enable PPP LCP Extensions check box to clear it, and then click OK.

Disable IP Header Compression

You may have problems logging on to your ISP if you are using IP headercompression (also known as Van Jacobson or VJ header compression). Todisable IP header compression, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click the Server tab, and then click TCP/IP Settings.
  5. Click the Use IP Header Compression check box to clear it, and then click OK.
  6. Click OK.

Connect Using a Terminal Window

Some PPP and SLIP accounts require you to log on using a terminal window,and then type "PPP" or "slip" (without quotation marks) at a terminalprompt to start the session. When you log on, you may also need to prefixyour user name with characters such as "P" or "S" or "PPP:" (withoutquotation marks). Contact your ISP to determine if you must type "ppp" or"slip" at a terminal prompt or if your user name requires a specialprefix.

If your ISP requires additional information other than your user name andpassword, you may need to use a terminal window. To open a terminal windowafter you connect, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click the Script tab, click Pop Up A Terminal Window, and then click OK.

No Prompt for Username and Password

If you do not receive a prompt for your user name or password when youattempt to connect to your ISP, follow these steps:
  1. Click Start, point to Programs, point to Accessories, and then click Dial-Up Networking.
  2. Click the phone book entry for your ISP in the Phonebook Entry To Dial box.
  3. Click More, and then click Edit Entry And Modem Properties.
  4. Click the Security tab, click Unsave Password, and then click OK.

Disable Your Login Script

If you run a login script to connect to your ISP, disable it and try toconnect with a pop-up terminal window. If you are able to connect, theremay be a problem with your login script file. You may need to contact yourISP for assistance in creating a script file to use with Dial-UpNetworking. Windows NT includes several basic script files including:
  • Ppp.scp
  • Slip.scp
  • Cis.scp
NOTE: When you use the CompuServe Information Service (CIS) script, youmust use your CIS ID for your user name. For more information about usingthese files, view the Script.doc file in the Winnt\System32\Ras\Scriptfolder. If you have problems creating a script file to automate your logon, contact your ISP for further assistance.

If you have a SLIP account, you must use a terminal window or a scriptfile to connect to your ISP. When you are using a SLIP account, most ISPsdisplay your IP address for the session in the terminal window. Most ISPsinform you of your IP address with a message similar to "Your IP addressis <###.###.###.###>" or "SLIP session from <###.###.###.###> to<###.###.###.###>." In this case, the second number is usually your IPaddress. You should enter this in the IP Address box. If the address isthe same every time you connect, you can change it in the phone book entryin TCP/IP settings on the Server tab.

Verify the Phone Number

Verify that you are using the correct phone number to connect to your ISP.If you use MSN, The Microsoft Network, as your ISP, verify that you aredialing in to an MSN phone number that supports calls for the service type"Internet and the Microsoft Network."

Mutual Authentication

You may have problems logging in to your ISP if your ISP's PPP server isusing mutual authentication. Dial-Up Networking does not support mutualauthentication. Contact your ISP to determine whether your ISP's PPPserver uses mutual authentication.

PPP Logging

Enabling the PPP logging file (Ppp.log) may help you troubleshoot otherproblems related to connecting to your ISP's PPP server. For informationabout how to enable the Ppp.log file, see the following article in theMicrosoft Knowledge Base:
ARTICLE-ID: 115929
TITLE : Enabling PPP Logging in Windows NT
NOTE: If you are using routing and the Remote Access Service Update, theabove Microsoft Knowledge Base article does not apply. For informationabout enabling logging in this situation, see the following article in theMicrosoft Knowledge Base:
ARTICLE-ID: 161426
TITLE : How to Enable Logging with Routing and Remote Access
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Article ID: 161986 - Last Review: 12/04/2015 16:06:41 - Revision: 2.1

Microsoft Windows 2000 Server, Microsoft Windows 2000 Advanced Server, Microsoft Windows 2000 Professional Edition, Microsoft Windows 2000 Datacenter Server, Microsoft Windows NT Server 4.0 Standard Edition, Microsoft Windows NT Workstation 4.0 Developer Edition

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