Modify htaccess to show 404 error

[websitings]

Greetings,

My website displays dynamic content from urls like this:

[a href=\"http://www.mydomain.com/index.php?f=whatever\" target=\"_blank\"]http://www.mydomain.com/index.php?f=whatever[/a]

Is it possible to modify the htaccess so that if a url does not contain ?f a header 404 message instead of a 200 success could be presented to the agent requesting the url.

Thanks for any assistance

[zq29]

I know you can force users to a 403 (Forbidden) by using mod_rewrite in a .htaccess file. If that interests you, check the mod_rewrite section of the Apache manual, its in there somewhere.

[mtbrandall]

try just doing it in php and adding
[code]
<?php
if(!isset($_GET['f'])){ //see if ?f is not set
    header("Location: error404.php"); //send the user to the 404 page
    exit(); //terminate the script
}
?>
[/code]