One of my little web twitches is the lax handling of unknown query parameters . As part of this twitch I've long been a bit irritated that Apache accepts query parameters even on static files, when they definitely have no meaning at all. You could say that this is merely Apache being accepting in general, but recently I noticed a combination of Apache features that can provide an additional reason for Apache to do this.

Apache has various features to redirect from old URLs on your site to new URLs, such as Redirect and RewriteRule . As covered in the relevant documentation for each of them, these rewrites preserve query parameters (although for RewriteRule you can turn that off with the QSD flag ). This behavior makes sense in a lot of cases; if you've moved an application from one URL to another (or from one host to another) and it uses query parameters, you almost certainly want the query parameters to carry over with the HTTP redirection that people using old URLs will get.

(Here by 'an application' I mean anything that accepts and acts on query parameters. It might be a CGI, a PHP page or set of pages, a reverse proxy to something else, a Django application implemented with mod_wsgi , or various other things.)

A lot of the time if you use a redirect in Apache on URLs for an application, you'll be sending people to the new location of that application or its replacement. However, some of the time you'll be redirecting from an application to a static page, for example a page that says "this application has gone away". At least by default, your redirection from the application to the static page will carry query parameters along with it, and it would be a bad experience (for the people visiting and you) if the default result was that Apache served some sort of error page because it received query parameters on a static file.

(A closely related change is replacing a single-URL application, such as a basic CGI, with a static web page. Maybe the whole thing is no longer supported, or maybe everything now has a single useful response regardless of query parameters. Here again you can legitimately receive query parameters on a static file.)

Realizing this made me more sympathetic to Apache's behavior of accepting query parameters on static files. It's a relatively reasonable pragmatic choice even if (like me) you're not one of the people who feel unknown query parameters should always be ignored (which is the de facto requirement on the modern web , so my feelings about it are irrelevant).