I recommend that you inspect the HTTP headers first since they are simple key-value pairs, and generally, there are only a few returned with each request. It doesn't take very long to go through the headers manually, so you can inspect them first before moving on to the application. Fingerprinting at the application level is more complicated and we'll talk about that in a moment. Earlier in this chapter, there was a section about extracting HTTP headers and printing them out for inspection (the Extracting HTTP headers from an HTTP response section). You can use that program to dump the headers of different web pages and see what you can find.
The basic idea is simple. Look for keywords. Some headers ...
