Make sure you have a .htaccess and .htpasswd file in the directory you want to secure, then add the entries once you've generated your password.

Creating custom documents gives your site a more professional look, as not only are you providing a 'net' to catch unsuspecting visitors when they follow a bad link and such like, but they also allow you to customise the style of the page so you can maintain your basic site design by adding HTML.

Control Access

Being able to control access to certain areas of your server can be very useful. The following example demonstrates how to only allow access from those connecting from a 192.168.0 LAN IP pool. This could be easily modified to only allow access from a single remote IP address or addresses.

Hide and Deny Files

Hiding and denying access to files is crucial to servers that have sensitive data held within files that may be accessible via the website(s) on it. The following example demonstrates how to prevent acces to any files ending with .log - and is case insensitive (i.e. .LoG / .lOG / .loG).

Basic Rewriting

I have written a mod_rewrite tutorial, but this is worth a mention as a top 10 tip for .htaccess files as it's becoming more and more commonly used these days - primarily for SEO purposes.

This example will redirect a request for http://edrackham.com/page_one.htm to http://edrackham.com/page_one.php. The r=301 tells apache to send a proper HTTP Permanently Moved redirection (301), which will update the address bar in the browser window to show 'page_one.php'. Without this, you'd still see 'page_one.htm' even though you're seeing a PHP page. This helps SEO, as spiders and search engines will update their listings to reflect the PHP versions.

Shorter URLs

Shorter URLs are beneficial, as visitors that persist in typing full URLs won't have to type as much, and they're more memorable. Do they benefit SEO, even though the full URL contains the same keywords? I don't know, maybe someone can tell me.

This example will rewrite a page requested as http://edrackham.com/files/code/apache.zip to http://edrackham.com/download.php?type=code&file=apache.

Prevent Hotlinking

Preventing hotlinking can reduce bandwidth, by disallowing other websites from displaying images hosted on your server. The following rule basically says that if the referer is NOT edrackham.com, run the following rule. The rule (on the next line) says that if the request is for a .gif, .jpg or.png then redirect the visitor to http://edrackham.com/img/hotlink_f_o.png. I'll leave you to work out what the 'f_o' stands for.

Hiding Page Extension

Similar to the mod_rewrite code above, this will redirect a request for product-3.html to products.php?id=3. As we're not using r=301, the requested page will remain in the browser's address bar.

Ban Selected User Agents

In my opinion, it'd be ace to block all requests from a Microsoft user agent, but alas, that wouldn't be too cool as some people are still hell-bent on using a non-standards compliant browser. Having said that, Microsoft is making their new IE8 release standards compliant by default.

The following provides some examples for blocking requests to your server from certain user agents.

Making Other Filetypes Executable

Ever wanted to make your site look like it runs off a new language such as .w00t files? Well you can with .htaccess! Adding this neat one-liner, you can request .w00t files, which will be served and interpreted as .php type files.

Force Media Downloads

Sometimes, when clicking on media files, the browser wants to play or stream it directly from itself. Using the following rules, media files (.avi/.mpg/.wmv/.mp3 in this example) will provide a download dialog box instead.

Require SSL

Sometimes you will require an SSL connection. This following snippet will do just that!

Sources:
http://corz.org/serv/tricks/htaccess.php
http://roshanbh.com.np/2008/02/hide-php-url-rewriting-htaccess.html
http://expressproducts.net/htaccess.htm
http://perishablepress.com/press/2006/01/10/stupid-htaccess-tricks/#usa4
http://phpsecurity.wordpress.com/2007/12/22/htaccess-tips-and-tricks/

(more…)