As a consultant, I've spent many years helping clients with hardware, software, and network problems. One thing I've noticed is that the most common—and most frustrating—way people report a problem is to say "I can't..." or "The computer won't...". Unfortunately, knowing what doesn't happen isn't helpful at all. 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. So, start by trying to express whatever problem you're having in terms of what is happening, not what isn't.
And extending that principle, 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. For example, check to see whether a problem affects just one computer or all the computers on your local area network (LAN). If other computers can manage the task that one computer is having trouble with, you know that the problem is located in that one computer, or in its connection to the others.
The following are some other questions I always 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, can you 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
If you can determine which category a problem falls in, you're halfway there. At that 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 of them, 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 outline these tools and suggest how to use them.