Using Apache to Debug Apache

There are number of Apache modules that can help you when troubleshooting or debugging an Apache setup or a web application.

mod_loopback, a Web client debugging tool, simply echoes back to the browser everything received concerning an HTTP request, including POST or PUT data.

http://www.snert.com/Software/mod_loopback/index.shtml

mod_tee and mod_trace_output are third-party modules that store the content as it is being served. They can be found at these URLs:

http://apache.webthing.com/mod_tee/ http://trace-output.sourceforge.net/

mod_logio, distributed with Apache 2, dumps all data received or returned by the server into the error log for debugging purposes.

All of these modules have an effect on performance, but can be very useful when debugging, for example, header or cookie-related issues.