Troubleshooting networks

Jasiono

Is there a certain "formula" that someone has that is effective when used to troubleshoot networks?

This is my weakest area. Not that I don't know the material, it's just a lot of information that I think about that causes me to lock up.

One problem I have is that I don't think of the simplest reasons first (such as a cable being bad), and tend to get caught up within the higher levels of things that could be wrong.

digitheads

kind of vague question, what is the complaint ? in general, start with the physical of it all. make sure all your hardware is functioning properly, all of your connections are good, and they are running at the expected speed and duplex. beyond that, you need to determine where the problem exists and concentrate on this are of the network, but here again you need to know in general what the user complaint is.

Jasiono

It's for the exam actually.

I read something about:

Find out where a packet needs to go and follow the path it's taking.
Figure out where the packet stops going where you expected it to go and check the settings.

I guess that's a general type of formula.

Then I have to see how that particular area is set up, such as the protocols involved and such.

Stevecb06

In this situation you could use traceroute to show you where communication breaks down. Traceroute will send a packet to each hop along the way to the destination, and you will be able to see which hop fails to respond. You will then know that it is that device, or perhaps the one before it that has an issue. You can then focus your troubleshooting efforts to those devices, checking things like cabling, IP addressing, interface configurations, etc...

networker050184

Troubleshooting comes easy with understanding. If you know the ins and outs of the technology you can start to see the gaps when something isn't working. You can see it in the posts people make here, or in the support queue at work. A fundamental understanding of the technology would solve 90% of the issues. When you've labbed it enough times you've broken it yourself in pretty much every way it can be as well.

As far as methodology, start from the bottom of the OSI. Is the physical up? How's your L2 looking? Can you see MACs? Is the routing there? Work your way up.

quickman007

networker050184 wrote: »

Troubleshooting comes easy with understanding. If you know the ins and outs of the technology you can start to see the gaps when something isn't working. You can see it in the posts people make here, or in the support queue at work. A fundamental understanding of the technology would solve 90% of the issues. When you've labbed it enough times you've broken it yourself in pretty much every way it can be as well.

As far as methodology, start from the bottom of the OSI. Is the physical up? How's your L2 looking? Can you see MACs? Is the routing there? Work your way up.

This ^^^

I have a coworker who doesn't have a great understanding of the technology and his troubleshooting skills are lacking because of this. Hard to troubleshoot a routing issue when you don't know how routing works. Obviously experience will help as well.