How can I find out which technologies were used to generate a website?

Question

How can I find out which technologies were used to generate a website? Is it possible?

E.g. PHP, JSP, JSF, ASP.NET, Ruby, Python etc.

Answer 1

Unless the URL reveals it (e.g. http://something/blah.php), you can't. Even the URL is not reliable, as you theoretically could configure a web server to use the .php extension for Java Server Pages. It's weird, but it's possible. The same goes for all possible combinations.

As all of those are server side languages, the only thing you can see as the client is HTML. HTML by itself does not reveal a lot.

You might be able to find out more by inspecting the HTML markup and looking for some keywords. For example, some web frameworks or templating engines leave traces and special patterns or keywords that might give you a hint. It's very specific though and I don't know of any tool that would to this kind of task (except for Google, that is).

Answer 2

• There are online tools for determining which web servers are used on a given site:

http://uptime.netcraft.com/up/graph?site=superuser.com

But these are highly unreliable, because the information a server reveals can be easily manipulated or hidden by the site owner (which might lead to the remark "unknown" as the server type in this particular chart).

• Another option is to call an non-existing page on a site. The error message (404) might also reveal the OS and the server software:

http://lexin2.nada.kth.se/test ("test" does not exist) reveals that they are using Tomcat with Apache. In a similar way, you will see messages from Microsoft IIS on Windows, PHP on Linux, etc.

Most sites replace though the standard 404 message with a more informative one, like this site's: http://superuser.com/test So there's not much to gather there.

• Some sites started changing the file extensions, like to "svd" ("SVD" is the shortname of the newspaper). This method makes it harder to detect which scripting engine is used: http://www.svd.se/kultur/sangerskan-amy-winehouse-dod_6343850.svd