Keep an Eye on Your Web Site in Real Time
IISTracer helps spot questionable activity fast.
If you'd like to monitor your Web site in real time, take a look at PSTRUH
Software's IISTracer (see Figure). IISTracer is an ISAPI (Internet Services
API) library that you load directly on your IIS server. If you're not
familiar with ISAPI, this is a technology that gives you a chance to "hook"
requests to your server before IIS processes them. An ISAPI DLL can either
modify the HTTP requests (or even throw them away if they're deemed too
dangerous to process) or pass them on intact to the rest of IIS.
IISTracer only looks at requests, without changing them. It sits unobtrusively
in the background, monitoring traffic and displaying the current activity
on screen. You can configure a variety of options, including a threshold
for long-running requests so that the monitoring screen will show only
files that are taking a long time to deliver. This can be an excellent
way to find files on your site that are causing a performance problem.
You can also log problem activity for future analysis.
In addition to giving you a feel for the patterns of activity on your
server, IISTracer can be an effective way to spot an attack in progress.
Spotting the pattern of unusual URLs sent by Code Red or a bunch of long-running
connections in a denial-of-service attack may let you take immediate corrective
action. Screentips on the IISTracer display even show you the HTTP headers
sent to your server, so you can see which browsers your customers are
using or which sites are sending traffic your way.
| IISTracer provides real-time Web site monitoring, including
a look at recently delivered pages and the HTTP headers that retrieved
them. (Click image to view larger version.)
In my tests, IISTracer worked well and did exactly what it was advertised
to do. I ran it on a live Web server, and from the outside you couldn't
tell that anything was different. But from the inside, I suddenly had
much more diagnostic information at my fingertips.
Mike Gunderloy, MCSE, MCSD, MCDBA, is a former MCP columnist and the author of numerous development books.