It can happen if you upgrade Apache and/or mod_php, and for some reason mod_php fails to register for .php files without being a fatal startup error. Then apach

It can happen if you upgrade Apache and/or mod_php, and for some reason mod_php fails to register for .php files without being a fatal startup error. Then apache will serve the .php files as plaintext. It's one of the things that make one-off .php scripts easy to deploy (just chuck it into the webroot). With a little effort, this can be mostly prevented: let the webroot .php file just do an ' include("../outside-webroot/actual-script.php"); '