Network monitoring/analyzing

[AD53]

Hello. I hope this is the correct forum to post this question...

Does anybody have a recommendation for a good application that can monitor the network to see what kind of network traffic is out there and do network analysis (bottlenecks, bad packets, bad NIC, etc)...and is user friendly?

I have been 'volunteered' into the IT dept. Our problem is that the network (and Internet) connection is very slow. Unfortunately, we have no network documentation to speak of. We do have multiple Cisco and HP switches. From what I am told, the Cisco switches were configured by a consultant. To add to the problem, I do know that there are many users in the company that is audio and video-streaming.

Since I am new to this stuff, I was wondering if there is any good application out there that can monitor the network to see what is making the network so slow - like identifying who is doing the audio/video-streaming or if we have bad hardware sending out bad packets, etc. Appreciate all your help. Thanks!

 

[lerdalt]

WOW...where to begin. Any packet analyzer will probably be a good start just to monitor the connection going to the internet. Network General, Wildpackets, Observer, would all be of good benefit to you. Using one of those applications should help you to identify who is doing the streaming, or at least your top talkers across certain connections are.

I shouldn't forget that depending on your firewall to the internet you might be able to pull the same sort of information.

If you have a Cisco router that is connecting you to the internet, look up how to enable netflow. Thats another good way to see your top talkers, but not as 'pretty' as a packet analyzer will display it for you.

You will want to determine if the slowness is just to the internet or if its something else within your LAN. Do some ftp transfers (I prefer doing it from the command line toget good output on bytes transfered and times). I like setting up one computer as an ftp server and move between VLANS or LAN segments with another laptop, just to see if there is much variation.

If it is just the connection to the internet, check your firewall logs...make certain you don't have a worm that's killing your connection. Had that happen to me too many times.

The slow network is always fun to fight, especially if you don't have network documentation or at least a good picture of how it is laid out in your head. You will probably want to start first by creating some quick maps, and try to isolate what areas and what applications are having problems.

Good luck.

 

[PalmTest]

Hi AD53,

Welcome to the wonderful world of Networking.
As lerdalt suggested you can enable Netflow on a Cisco router, if the Cisco box supports it.
A free Netflow tool which can come in handy is NTop.

http://www.openxtra.co.uk/products/ntop-xtra.php

This is a NTop package with no limitations (AFAIK).

Another free tool which I always use is MRTG.
Look at the friendly guy who gave us this brilliant piece of software.

http://oss.oetiker.ch/mrtg/

A complete package with all the bells 'n whistles can be found at:

http://www.openinnovations.com/mrtgbundle.html

Scroll down to download the MRTG2 bundle.

 

[fortunat]

I've got some info on my site.. help yourself

'Making things work better; bit by bit.'