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By John Jacobs

ABSTRACT: Highlighting content available on the Microsoft Systems Professional web site and the TechNet CD, this article helps you troubleshoot Windows 95 Dial-Up Networking problems and find related articles, and provides sample queries that demonstrate effective ways to locate information.

Support professionals need to know how their customers are affected by computing trends. An important trend today is increasing communication between PCs using networks, the Internet, and telecommunications lines. Windows 95 supports this trend with Dial-Up Networking, a component that lets a Windows 95 computer connect to a network using a modem instead of a network adapter. Many support specialists want to research this important feature so they can answer the most common end-user questions quickly, but they are unsure where to start because Dial-Up Networking overlaps several other topics, such as hardware support and general networking.

You can match many common questions to those listed below and get a quick answer, pointers to specific articles, and advice on finding more information.

Many topics refer by title to articles in the Windows 95 Knowledge Base and the Windows 95 Resource Kit. These sources are available on TechNet and on Microsoft's Web site:


Location on TechNet

Location on the Web

Windows 95
Knowledge Base

Personal Systems; Windows 95; Knowledge Base

Windows 95
Resource Kit

Personal Systems; Windows 95; Resource Kit

Knowledge Base articles are referenced by "Q" number and title, as below:

  • Q94671 Categories and Keywords for All Knowledge Base Articles

Windows 95 Resource Kit articles are referenced by title and part or chapter number, as below:

  • Windows 95 Resource Kit; Chapter 35 General Troubleshooting

Articles on the World Wide Web are referenced by title and URL, as below:

Understanding the Technology

This section briefly summarizes Dial-Up Networking and provides references you can use when training support staff and explaining the product's features and limits to users.

What is Dial-Up Networking?

Dial-Up Networking is a Windows 95 component. It lets a Windows 95-based computer connect to a network using telecommunications hardware, such as a modem and telephone lines, instead of a network adapter and network cables. A "remote access" server on the remote network runs corresponding software with which it grants dial-up clients access to shared resources. In most cases, this server is a computer running Windows NT Server, but it can be a special-purpose device (such as a Shiva Lanrover) instead of a computer, and it can run Windows 95 (see below), Windows for Workgroups, Novell NetWare, or UNIX. If the server is a computer it can give clients access to its own shared files and printers, and in most cases to other networks it is connected to.

The best technical treatment is the Windows 95 Resource Kit, Chapter 28 Dial-Up Networking and Mobile Computing. The introductory material and the first section, Overview of Dial-Up Networking, are good summaries for end users.

What Roles Can Windows 95-based Computers Play?

Windows 95 is usually a Dial-Up Networking client, but can also be a remote access server. Dial-Up Networking Server software is included with Plus! for Windows 95, but not with Windows 95.

For detailed information about Dial-Up Networking Server, see 139710 How to Enable Dial-Up Networking Server Capabilities, and the Windows 95 Resource Kit, Chapter 28 Dial-Up Networking and Mobile Computing; Configuring Dial-Up Networking Clients and Servers; Configuring a Windows 95 Dial-Up Server.

What are the Requirements?

The Dial-Up Networking client and server software both require Windows 95, a supported telecommunications device (typically a modem), and two or three megabytes of disk space.

For more detail about system requirements see the Windows 95 Resource Kit; Chapter 28 Dial-Up Networking and Mobile Computing; Dial-Up Networking and Mobile Computing: The Issues.

To determine whether a modem is supported, see 131900 Windows 95 Hardware Compatibility List, or search the Knowledge Base for the keywords "windows 95" "hardware compatibility list".

Related Topics

Dial-Up Networking is the intersection of two broad topics: networking and serial communications. Many support engineers want to improve their knowledge of one of these. The best source is the Windows 95 Resource Kit; Part 3 (Chapters 7 through 12) cover networking, Chapter 19 covers support for peripheral devices, and Part 6 (Chapters 24 through 30) cover communications.

In addition, these articles cover specific, important topics:

  • 123992 Basic Configurations for COM Ports in Windows 95

  • 130402 Device Contention in Windows 95

  • Hardware and Multimedia Questions

Answering "How to" Questions

This section covers common questions people ask when they don't know how to perform an action such as installing hardware or software. The next section covers problems they encounter once they know what to do.

How Do I Install and Configure an Internal Modem?

The article most specific to this question is 152064 How to Install an Internal Modem in Windows 95. If you want general information about installing hardware, see 142984 How to Install New Hardware in Windows 95.

How Do I Use ISDN with Win95?

ISDN is a digital telephone service that offers throughput as high as 128 Kb/s. If you are not familiar with ISDN, see 149552 ISDN Terms and Definitions.

ISDN hardware may be an internal adapter or an external serial device (analogous to an external modem). The external device is technically not a modem, but because it serves the same purpose Dial-Up Networking refers to it as a modem. For more information see 147866 Dial-Up Networking Refers to ISDN Adapter as a Modem. Several models are supported by files supplied with Windows 95; many more are supported with files supplied by the manufacturers.

Technically, internal ISDN devices are not supported, in the sense that when Windows 95 shipped none were listed on the Windows 95 Hardware Compatibility List. Windows 95 does detect certain ISDN adapters, but setting them up requires additional information from the adapter's manufacturer and your ISDN provider. For more information see 140123 Using ISDN Terminal Adapters in Windows 95. Support for an internal adapter requires files from the manufacturer, in addition to software supplied with the Microsoft ISDN Accelerator Pack. For more information see 145987 ISDN Accelerator Pack for Microsoft Internet Explorer 2.0.

For information about obtaining ISDN service, see 151664 Description of "Get ISDN for Microsoft Windows," or browse the Get ISDN page:

If you already have the ISDN Accelerator Pack and are encountering problems, see 148742 Troubleshooting the ISDN Accelerator Pack.

How Do I Install and Configure a PCMCIA Modem?

For instructions, see 133239 Enabling PCMCIA Support in Windows 95.

For general information about Plug and Play, see 133159 Plug and Play Support in Windows 95 Questions and Answers.

If you encounter problems, see 136553 Troubleshooting PCMCIA Cards in Windows 95.

For information about required socket services, or using PCMCIA cards in protected mode, see the "PCMCIA Cards" section of 135895 Windows 95 CD-ROM Faq.txt File (2 of 2).

How Do I Install and Use Dial-Up Networking Software?

If you want client software installation instructions, see the section titled Installing Dial-Up Networking in 145843 How to Connect to a Remote Server.

For information about installing both the client and server components, see the Windows 95 Resource Kit; Chapter 28 Dial-Up Networking and Mobile Computing; Configuring Dial-Up Networking Clients and Servers.

How Do I Dial a Mainframe, Connect to a BBS, or Remotely Control Another Computer?

These tasks require software that uses modems to carry keyboard, mouse, and video signals between two computers. Dial-Up Networking, in comparison, uses modems to carry network frames between a computer and a remote network.

To dial a mainframe or connect to a BBS you need a terminal emulator such as HyperTerminal (supplied with Windows 95). For information about HyperTerminal, see the Windows 95 Resource Kit, Chapter 25 Modems and Communications, Using HyperTerminal, or query the Knowledge Base for the word HyperTerminal. Microsoft does not make remote control software, but other vendors do.

How Do I Configure and Use Dial-Up Networking for Internet Access?

If you want a detailed treatment of the general topic, see the Windows 95 Resource Kit; Chapter 30 Internet Access, especially Connecting to the Internet; Making a Dial-Up Networking Connection.

If you access the Internet through an Internet Service Provider (ISP), see 138789 How to Connect to the Internet in Windows 95. If you access the Internet through CompuServe, see Q14249 How to Connect to the Internet Using DUN and CompuServe.


To find "how to" Knowledge Base articles query using the keyword kbhowto. Narrow the query with other terms, such as modem or PPP, or additional Knowledge Base keywords, such as:

  • win95—Windows 95

  • dun—Dial-Up Networking

  • kbhw—Hardware

  • kbnetwork—Networking

  • kbfaq—Frequently asked questions

  • kbreadme—README files

Solving Problems


Troubleshooting a Dial-Up Networking problem starts with gathering information about three factors:

  • Symptoms—How do you know something is wrong? For example, an error message, inability to perform an operation, or other unexpected behavior.

  • Timing—When did the problem start? For example, have the symptoms always occurred? If not, what time and day did they begin? What events immediately preceded or coincided with the symptoms?

  • Reproduction—What minimal conditions are required to reproduce the problem? For example, is it specific to a particular user, client, server, or modem, or to a group of them? To one sequence of keystrokes or mouse clicks? To one modem-aware application or to several (such as Dial-Up Networking and HyperTerminal)?

The information you gather may identify the problem, or determine the troubleshooting steps. For example, if the symptom is an error message, you can query the Knowledge Base using key words from the message. If the system was working properly until the modem's BIOS was upgraded, you should query on the modem's make and model, or on the BIOS revision. If one user cannot access a shared file, but other users can when logged into the same computer, you should suspect a permissions problem.

If the information does not suggest a cause, or initial troubleshooting is unsuccessful, determine which of the following actions the user was performing when the problem occurred:

  • Installing hardware

  • Installing software

  • Dialing a server

  • Connecting to a server after successfully dialing

  • Accessing a shared resource after successfully connecting to the server

Next, go to the subsection below that matches the user's action, and look for a topic that matches the symptoms.

Problems Installing Hardware

Many problems reported against Dial-Up Networking stem from misconfigured or incompatible hardware. The topics below include the most common hardware-related symptoms.

After using the Install New Modem Wizard, the COM port for that modem is not listed

This happens unless you run the Add New Hardware Wizard. For more information, see 130796 Cannot Set Up Internal Modem.

Modem is not detected at all

This almost always indicates a hardware configuration problem. Check for IRQ and IO Address conflicts. If the modem is external, also check for a defective serial cable or serial connector (9-to-25 pin connectors supplied with many serial mice often have pinouts that do not support modems).

The most common IRQ conflict is between serial devices that act as COM1 and COM3, or COM2 and COM4. For more information, see Q82545 Serial Device Stops Working After Installing New Serial Device.

Many other conflicts occur because of the way Windows 95 assigns IRQs and IO ranges for software configurable network adapters. For more information, see 126633 Network Card IRQ Conflicts with Another Device.

For background information on how Windows 95 detects hardware, and how to troubleshoot detection problems, see:

  • Windows 95 Resource Kit; Chapter 6: Setup Technical Discussion

  • 124560 Windows 95 Detection Manager Error Messages

  • 123815 Deciphering the Windows 95 DETLOG.TXT File

Modem detected as "Standard Modem"

Windows 95 detects a modem's make and model only if the modem was on the Windows 95 Hardware Compatibility List when Windows 95 was released. This does not mean that a modem not on the list will not work, but it may mean Windows 95 is not taking advantage of all the modem's features. For more information, see the Modems section of 135896 Windows 95 CD-ROM Hardware.txt File.

Dial-Up Networking stopped working after adding another device

Most such problems are caused by devices that use IRQ 3 or 4 and conflict with the modem that Dial-Up Networking is using. If the user added a serial device, see Q82545 Serial Device Stops Working After Installing New Serial Device. If the user added a network adapter, see 126633 Network Card IRQ Conflicts with Another Device.

Problems Installing Dial-Up Networking Software

Few problems occur during the installation of Dial-Up Networking software. The ones that do occur are usually general problems with hard disks, network connections, or permissions.

Problems Dialing a Server

Win16 communication software works, but Dial-Up Networking fails

People often say this when, in fact, they are exiting Windows 95, rebooting, and starting Windows 3.1 to test the 16-bit application. If this is the case, suspect an IRQ or IO conflict. For example, if a modem and network adapter both use IRQ 3, and the computer runs Windows 3.1, the modem will work with terminal emulator software if you don't activate the network adapter by running networking software. Booting Windows 95, however, starts up Dial-Up Networking, which creates the IRQ conflict.

If you are using an external modem, try resetting the flow control from Hardware to either Software or None. If this resolves the problem, suspect a defective serial cable or connector. The 9-to-25 pin connectors supplied with many serial mice often have pinouts that do not fully support modems, and such problems may appear with Windows 95 but not with other operating systems.

Error message: Modem is busy or not responding

  • This error can occur when multiple applications attempt to access a serial port at the same time, or when an IRQ or IO conflict occurs, or when certain registry values are corrupted. For more information, see 138634 Error Message: Modem is Busy or Not Responding.

Problems Connecting to a Server

Error message: "Dial-Up Networking could not negotiate a compatible set of network protocols"

To communicate, the Dial-Up Networking client and the remote access server must have at least one protocol in common, and must use the same authentication method. This error results if either of these conditions is not met. For more information, see 130079 Err Msg: Dial-Up Networking Could Not Negotiate Compatible...

Error messages: "Could not open http://<site>" or "The Internet site <site> was not found"

People using Dial-Up Networking to connect to the Internet receive these error messages when the TCP/IP protocol is incorrectly configured. For configuration instructions, see the Troubleshooting Tips section of 141159 Internet Explorer Err Msg: Could Not Open...

Accessing resources on a TCP/IP network

A Dial-Up Networking Server cannot communicate with a Dial-Up Networking client using TCP/IP, either to share the server's own files and printers, or to give the client access to the server's network. As a workaround, the client and server can communicate using IPX or NetBEUI, or the Dial-Up Networking client can communicate with other types of remote access servers using TCP/IP. Articles that detail this problem include 142543 Windows 95 Hangs with TCP/IP Routing Enabled, and the section titled Configuring a Windows 95 Dial-Up Server in 135849 List of Documentation Errors in Windows 95 Resource Kit.


General troubleshooting steps for connection problems include:

  • Verify telephone number, access codes, area code, and country code.

  • Make sure the correct server type is selected (for example, users often choose PPP but dial into a SLIP server). For more information see 148499 Differences Between SLIP and PPP with Dial-Up Networking, and 133187 How to Install a Point-to-Point Protocol in Windows 95.

  • Ensure the client and server use the same authentication method. For more information see 136634 Remote Access Services Authentication Summary.

  • Open the Terminal window after dialing to determine whether additional logon information is required.

  • If you are using an external modem, check the cable and verify that it is connected correctly.

  • Check the COM port configuration in Device Manager.

  • Make sure that compatible protocols are installed and bound to the dial-up adapter.

  • Try turning off software compression.

  • For Internet-specific information about this problem, see 138789 How to Connect to the Internet in Windows 95.

Problems Finding Shared Resources

Accessing resources through a NetWare Connect Server

Under these conditions, the error message "The network is not accessible" usually means the client or server is configured to use the 802.2 frame type instead of the 802.3 frame type. For more information see 137401 Cannot Access Network When Connected to NetWare Connect Server.

Unable to see a stand-alone Dial-Up Networking Server system in Network Neighborhood

The list of computers in the client's Network Neighborhood is compiled by the remote access server, so a stand-alone Dial-Up Networking Server computer cannot maintain that list. For more information see 145843 How to Connect to a Remote Server.

Accessing resources on a Windows 95 Dial-Up Networking server

The NET command does not show or connect to shared resources on a Windows 95 Dial-Up Networking Server computer if the "File and printer sharing for NetWare Networks" service is enabled. For more information see 139847 Cannot Connect Using NET Command with Dial-Up Networking.

If IPX is the only protocol the Dial-Up Networking Server can use to access its local network, and the server's IPX protocol is misconfigured, Dial-Up Networking clients cannot access shared resources on that network. For more information see 149454 Cannot Access Network When Connected to Dial-Up Server.

Other Related Issues

The sections above present the most common symptoms. Other symptoms are less common but still occur from time to time. Some occur while using Dial-Up Networking but are traceable to other causes.

You can find troubleshooting articles in the Knowledge Base by querying on the keyword kbtshoot. To narrow the search, include a keyword for the operating system, such as win95, and terms related to the topic, such as an error message, a modem make or model, an action (such as logon or browsing), a server type (such as SLIP, PPP, NetWare Connect, Windows NT, or Shiva), or a protocol (such as IPX or NetBEUI).

Also, you can find troubleshooting sections in several chapters of the Windows 95 Resource Kit, including:

  • Chapter 6 Setup Technical Discussion

  • Chapter 7 Introduction to Windows 95 Networking

  • Chapter 9 Windows 95 on NetWare Networks

  • Chapter 11 Logon, Browsing, and Resource Sharing

  • Chapter 12 Networking Technical Discussion

  • Chapter 25 Modems and Communications Tools


Dial-Up Networking is a broad topic, but learning about it and troubleshooting it need not be difficult. This article gives you a framework for understanding the issues, troubleshooting problems, and locating the most relevant information. With this framework, and access to the TechNet CD or Microsoft's Web Site, you have everything you need to deliver high-quality support to your customers.

Microsoft TechNet

September 1996
Volume 4, Issue 9