Network is running slow, what can I do to determine the cause?

[Punkrulz]

Alrighty guys, hopefully you can help me with this problem.

I work for a Circuit City, and here's how the network is setup for the computers and display computers.

We have a Wireless Linksys router. Comcast cable internet is connected to the router. The router is located under one of our desks on the floor. There are 4 computers that are hooked up to it directly. A lot of our laptops have wireless connections that are connected to the internet.

In the back where I do the installs, I utilize a lot of the Linksys Wireless USB Adapters to get online. However lately the network has been incredibly slow. What can I do to determine what computer is the culprit of the slow internet?

 

[Punkrulz]

Alright, now that I have some more time to be able to post, here's what I'm looking for:

I'm looking for an easy to use & understand program that is able to see all of the traffic going back and forth on all computers on the network, identify them by IP addresses, computer names, or otherwise to help identify them due to the fact that a lot of the computers are fresh out the box and don't have any specific information about them. This program would hopefully be able to tell me what's stealing all the bandwidth or what is causing the main problems for the internet, perhaps such programs as P2P transfers, AIM, etc.

Does a program like this exist?

Thanks guys!

 

[Admiral Michael]

Ethereal (http://www.ethereal.com) is a free program for viewing packets on a network. It will show the source, destination, comp names, etc.

Hope this helps.

 

[Punkrulz]

Ok, I finally have etheral capturing packets within the network. However, and I know there is a way to get a filter to filter this out (but I can't get it to work right), my packet monitor is overloaded with packets for spanning tree destinations and such.

How can I filter this out? I've read the help, and have tried a few different things, but can't get it to work correctly. :/

 

[koko]

how about some more information. what model of linksys wireless router and wireless adapters are you using? also, how many computers are on the network?

 

[Nick]

What have you tried so far with the filters? What's not working? What are you trying to do with the filters?

I'd suggest running a capture to a file, then looking at the capture and trying to analyse it rather than trying to analyse it in real time. I don't know what the firmware is like on linksys routers, but there might be an option to see who is connected to the wireless AP? Might be a good place to start.

Another program I've found useful in the past is ettercap, although it was a bit tricky to get running under windows IIRC although not too difficult under linux.