htaccess : Control access

.htaccess is most often used to restrict or deny access to individual files and folders. A typical example would be an "includes" folder. Your site's pages can call these included scripts all they like, but you don't want users accessing these files directly, over the web. In that case you would drop an .htaccess file in the includes folder with content something like this..

NO ENTRY!
# no one gets in here!
deny from all


which would deny ALL direct access to ANY files in that folder. You can be more specific with your conditions, for instance limiting access to a particular IP range, here's a handy top-level rule for a local test server..

NO ENTRY outside of the LAN!
# no nasty crackers in here!
order deny,allow
deny from all
allow from 192.168.0.0/24
# this would do the same thing..
#allow from 192.168.0


Generally these sorts of requests would bounce off your firewall anyway, but on a live server (like my dev mirror sometimes is) they become useful for filtering out undesirable IP blocks, known risks, lots of things. By the way, in case you hadn't spotted; lines beginning with "#" are ignored by Apache; handy for comments.

Sometimes, you will only want to ban one IP, perhaps some persistent robot that doesn't play by the rules..

post user agent every fifth request only. hmmm. ban IP..
# someone else giving the ruskies a bad name..
order allow,deny
deny from 83.222.23.219
allow from all


The usual rules for IP addresses apply, so you can use partial matches, ranges, and so on. Whatever, the user gets a 403 "access denied" error page in their client software (browser, usually), which certainly gets the message across. This is probably fine for most situations, but in part two I'll demonstrate some cooler ways to deny access, as well as how to deny those nasty web suckers, bad referrers, script kiddies and more.