Chapter 19. Troubleshooting Your Network

Everyone wants to live in a world without problems, but much to the chagrin of network operators everywhere, such a world doesn't exist. And when things go wrong, you have to be able to diagnose and correct (or at least work around) the issue. This chapter is dedicated to that aspect of networking. While we can't provide troubleshooting information for every conceivable problem, we can establish a framework that you can use to address most problems. As you continue to provision and manage your network, you'll find that having a systematic, repeatable approach to diagnosing and resolving issues is paramount for your success.

Following General Troubleshooting Tips

Whenever you find yourself in a troubleshooting situation, you can take advantage of some general tricks of the trade. None of the following tips are earth-shatteringly profound, but they're in line with the principle of keeping processes simple.

  • Look at your device. One of the easiest things you can do when diagnosing a problem is to actually look at the device. Take a peek to see whether all the interfaces are cabled correctly. If your problem is that an interface or line card is down, has it been plugged in correctly? If you happen to notice a black smear that is indicative of smoke or fire damage near a component, then you're most likely a bit closer to diagnosing the problem.

    Obviously, if you're managing remote devices, you probably don't want to hop on a plane and fly out to visually ...

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