When Good Networks Go Bad


Today's networks are so easy to install and configure that you can just Plug and Pray, er, I mean Play. But when good networks go bad, it's another story, one with all the makings of a Fox Network special.

Every time I get a call from a client with a network problem, I cringe. I never know whether it's going to take 10 minutes or a week to fix. Sometimes the problem isn't so bad; I've fixed more than one "broken" computer by turning it on. If such an easy fix doesn't present itself immediately, though, a bit of a cold sweat breaks out on my forehead. The problem could be anything. How do you even start to find a nasty problem in the maze of cards, wires, drivers, and hidden, inexplicable system services?

Well, if you work for a corporation with a network support staff, of course, the answer to that question is "Call the Help Desk!" or "Call Bob!" or call whatever or whoever is responsible for network problems in your organization. That's clearly the best way to go! Take a refreshing walk around the block while someone else sweats over your network. (If you're on your own, taking that walk might help anyway, before coming back to the job of discovering what the problem might be.) If you want or need to go it alone, though, the good news is that there are some tools provided with Windows that can help you find the problem. After talking about troubleshooting in general, I'll show you how to use them.

I will tell you that, in reading this chapter, you probably won't find the solution to any particular network problem you're having. I can't solve your problem here, but I can show you some of the tools available to help you identify the source of a problem you might have.

Getting Started

As a consultant, I've spent many years helping clients with hardware, software, and network problems. The most commonand frustratingway people report a problem is to say "I can't…" or "The computer won't…" Usually, knowing what doesn't happen isn't very helpful at all. To solve a mystery, you have to start with what you do know. I always have to ask "What happens when you try?" The answer to that question usually gets me well on the way to solving the problem. The original report usually leaves out important error messages and symptoms that might immediately identify the problem.

Also, as you work on a problem, pay as much attention to what does work as to what doesn't. Knowing what isn't broken lets you eliminate whole categories of problems. It also helps you to see whether a problem affects just one computer or all the computers on your local area network (LAN).

The following are some other questions I ask:

  • Does the problem occur all the time or just sometimes?

  • Can you reproduce the problem consistently? If you can define a procedure to reproduce the problem, try to reduce it to the shortest, most direct procedure possible.

  • Has the system ever worked, even once? If so, when did it stop working, and what happened just before that? What changed?

These questions can help you determine whether the problem is fundamental (for example, due to a nonfunctioning network card) or interactive (that is, due to a conflict with other users, with new software, or confined to a particular subsystem of the network). You might be able to spot the problem right off the bat if you look at the scene this way. If you can't, you can use some tools to help narrow down the problem.

Generally, network problems fall into one or more of these categories:

  • Application software

  • Network clients

  • Name-resolving services

  • Network protocols

  • Addressing and network configuration

  • Driver software

  • Network cards and hardware configuration

  • Wiring/hubs

To learn more information about networks and network components, If you can determine which category a problem falls in, you're halfway there. At this point, diagnostic tools and good, old-fashioned deductive reasoning come into play.

You might be able to eliminate one or more categories right away. For example, if your computer can communicate with some other computers but not all, and your network uses a central hub, you can deduce that at least your computer's network card and the wiring from your computer to the hub are working properly.

Windows comes with some diagnostic tools to further help you narrow down the cause of a network problem. In the rest of this chapter, I'll outline the tools and suggest how to use them. (You might also peruse Chapter 14, "Troubleshooting Your Internet Connection," for tips on diagnosing network problems specific to the Internet [TCP/IP] protocol.)



Special Edition Using Microsoft Windows XP Professional
Special Edition Using Microsoft Windows XP Professional (3rd Edition)
ISBN: 0789732807
EAN: 2147483647
Year: 2003
Pages: 450

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