This is a bandwith monitor.  If your Internet connection seems to be slow, PRTG can show you which protocols (HTTP, SMTP, etc.) are consuming the most bandwidth.  It will run on any modern OS (Windows 2000, Windows XP, Windows Server 2003, etc.)

There is a free edition available, as well as a commerical edition.  I've found the free version to be more than adequate.  It supports web-based reports as well as PDF reports.  The reports can be viewed real-time via a browser, or you can have them periodically emailed to yourself.

The Community Foundation of Sarasota County (CFSC) has been using the free edition for about a year.  We have it setup between their router and their LAN on an old Pentium III computer running Windows XP.  I have it configured to email a report (in PDF format) every evening that shows me the bandwith patterns for the past 24 hours.  I've been very happy with application.

For more information about this product, go to http://www.paessler.com/prtg.

 

 

Addendum (2/20/07)

I had been running PRTG version 5.1.1.473 flawlessly for just over a year, when it suddenly stopped working.  The web page with the graphs was no longer available.  When I tried to load the PRTG program manually, I got the following error:

Error: Access violation at 0x7C8024ED (tried to write to 0x00030D44), program terminated.

The problem started as soon as the Microsoft updates for Februrary 2007 were install on this machine.  The computer is a lowly Pentium III-866 Mhz system running Windows XP Pro Service Pack 2.  I have it set to automatically install all critical updates.  It rebooted itself after applying the latest critical updates from Microsoft, and then the PRTG service got an error when trying to load.

The fix was pretty easy.  I downloaded and installed the latest freeware version of PRTG from www.paessler.com (Version 6.0.6.625), and this fixed the problem.  I didn't even have to uninstall the old version.  I simply installed the new version over the existing version, and it kept all of my custom settings.  It's working flawlessly again.