Failed Request Tracing (also called FREB) is an IIS7 request-based tracing tool that helps figure out what exactly is happening to web server requests and why. Poor performance on some requests, authentication-related failures on other requests, or even server 500 errors from ASP or ASP.net were a nightmare to troubleshoot in previous IIS versions since the web server would never tell you much of what was going on. FREB simplifies the process by capturing the trace of the problem when it occurs and by showing you a granular view of what is happening at the web server level. In other words, Failed Request Tracing allows you to look under the hood of your car and plug in a diagnostic tool that can tell you what is wrong with any of the engine components.
To use FREB, developers or web server/site administrators simply create a set of rules that will trigger a trace. Once triggered, FREB will log that request to disk and pull in all the relevant trace information.
Once a trace output is created the IT professional looking at the XML based output with a browser may easily determine if the problem is web server or code related.
Rules may be created that can trace virtually any request on the server, including PHP or other development frameworks. This is a similar feature that is also part of the ASP.net framework which by the way may also be integrated with the FREB output as long as you have tracing enabled for your asp.net application.
This short video tutorial demonstrates the entire FREB process with a PHP based website.
In order to enable this feature on shared hosting services you must contact our support staff as it does require some higher level administrative tasks that are not yet delegated in IIS 7. It is also important to mention that there is some overhead associated when FREB is turned on and therefore it is good practice to have it turned off when you know your site is running with no known problems.
You can learn more about FREB and Windows 2008 hosting by visiting our knowledgebase or by visiting appliedi.net/iis7-hosting.