Your website can be accessed with www.domain.com and domain.com. Since Google penalizes this due to duplicated content reasons, you have to stick your domain to either www.domain.com or domain.com.
But – since some links are outside of your website scope and the search engines already have indexed your website under both addresses, you can’t change that easily.

Solution:

Do a 301 redirect for all http requests that are going to the wrong url.

Example 1 – Redirect domain.com to www.domain.com

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^www.domain.com$ [NC]
RewriteRule ^(.*)$ http://www.domain.com/$1 [L,R=301]

Example 2 – Redirect www.domain.com to domain.com

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^domain.com$ [NC]
RewriteRule ^(.*)$ http://domain.com/$1 [L,R=301]

Related posts:

1. how-to-redirect-a-webpage
2. Guide to htaccess and mod_rewrite
3. Beginners guide to .htaccess file with examples – Part II

The easiest htaccess trick is to make sure that your site doesn’t have any canonicalization issues on the homepage.

A lot of websites suffer from poor search engine rankings by having a number of different versions of the homepage, for example:

http://www.yoursite.com

http://yoursite.com/index.html

These pages are all seen as different urls, despite them having exactly the same content in most cases. Google has got better at deciding which version to use over the past 12 months but you can still run into problems.

To solve this issue simply add the following to your htaccess file:

Options +FollowSymLinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^yoursite.com
RewriteRule (.*) http://www.yoursite.com/$1 [R=301,L]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /index\.html\ HTTP/
RewriteRule ^index\.html$ http://www.yoursite.com/ [R=301,L]


This will redirect all versions to http://www.yoursite.com

Changing html files to php

Sometimes you might have a static html website and need to use php code on the html pages. Rather than redirecting all your html pages to the equivalent php versions you simply need to tell your server to parse html files as if they were php.


AddHandler application/x-httpd-php .html


This works with any files so if you want to create dynamic xml or asp files that behave like php files you simply edit the code as required:


AddHandler application/x-httpd-php .xml
AddHandler application/x-httpd-php .asp


Error pages

Custom error pages can be set up in cpanel fairly easily, if you want to create a custom error page in htaccess instead use this line:


ErrorDocument 404 http://www.yoursite.com/404.php


Directory Indexes

To avoid Google indexing your directory indexes you might need to specify an index page for your directories. This is not required on some servers.


DirectoryIndex index.php3


My preference is to redirect the directory index page to either the homepage or another suitable page. For example www.yoursite.com/images/ can normally be redirected to www.yoursite.com and www.yoursite.com/forum/ can normally be redirected to www.yoursite.com/forum/index.php

Redirecting pages

A nice simple use of htaccess is to redirect one page to another:


redirect 301 /old-page.php http://www.yoursite.com/new-page.php


Sending your feed to Feedburner

If you want to switch your feed to the Feedburner service you will need to redirect your current feed to the new http://feeds.feedburner.com/yourfeed location.

The redirect needs to apply to all users except the Feedburner spider:


RewriteCond %{HTTP_USER_AGENT} !FeedBurner
RewriteRule ^your-feed\.xml$ http://feeds.feedburner.com/your-feed [R,L]


Advanced hotlink protection

If you want to block other websites from hotlinking your images, but allow indexing of your images in the Google, Yahoo and MSN image search engines, you should use the code below:


RewriteEngine on
RewriteCond %{HTTP_REFERER} .
RewriteCond %{HTTP_REFERER} !^http://([^.]+\.)?yoursite\. [NC]
RewriteCond %{HTTP_REFERER} !google\. [NC]
RewriteCond %{HTTP_REFERER} !search\?q=cache [NC]
RewriteCond %{HTTP_REFERER} !msn\. [NC]
RewriteCond %{HTTP_REFERER} !yahoo\. [NC]
RewriteCond %{REQUEST_URI} !^/hotlinker\.gif$
RewriteRule \.(gif|jpg|png)$ /hotlinker.gif [NC,L]


The hotlinker.gif image is a custom image that you have created. I suggest using something like “This image was hotlinked from www.yoursite.com” and your logo.

My personal preference is to allow hotlinking but to implement a solution to make use of Google Images and hotlinkers to build links to your site.

Create beautiful url’s with mod_rewrite

The Apache rewrite engine is mainly used to turn dynamic url’s such as www.yoursite.com/product.php?id=123 into static and user friendly url’s such as www.yoursite.com/product/123


RewriteEngine on
RewriteRule ^product/([^/\.]+)/?$ product.php?id=$1 [L]


Another example, rewrite from:

www.yoursite.com/script.php?product=123 to www.yoursite.com/cat/product/123/


RewriteRule cat/(.*)/(.*)/$ /script.php?$1=$2


Removing query strings

Some websites like to link to you by adding an query string, for example I could link to www.yoursite.com/index.php?source=blogstorm just so you know where your traffic came from. This creates duplicate content issue for your site so you really need to redirect back to your homepage:


RewriteCond %{QUERY_STRING} ^source= RewriteRule (.*) /$1? [R=301,L]

Related posts:

1. Beginners Guide to .htaccess File with Examples
2. Beginners guide to .htaccess file with examples – Part II
3. Hide .php extension with url rewriting using .htaccess

First method requires, to create a new fail let’s call it my_false_email@not_exisiting.com, if you are unsure then: YES, file should be named like a valid email address, any UNIX system should handle such file. Next thing we need to do is add following lines in .htaccess file:

<filesMatch "my_false_email@not_exisiting.com">
ForceType application/x-httpd-php
</filesMatch>

Now our file will be executed as a PHP script, so open it and put there following script:

<?php
header('Location: mailto:my_real_email@my_real_domain.com');
?>

When someone tries to access file my_false_email@not_exisiting.com default email software will open with your real email address. Such solution will never expose your email address to email harvester, however there are also few downsides of this method. First it requires to create additional file, second if someone wants to copy your email from the website and then use it, then obviously he will get the fake email and won’t be able to contact you.

First problem can be resolved by using my modification to this method, instead of creating additional file, we can use redirection, put in .htaccess following line:

RedirectMatch my_false_email@not_exisiting.com mailto:my_real_email@my_real_domain.com

Now whenever in the URL my_false_email@not_exisiting.com will be found, email application will open, just like when you would click link mailto:my_real_email@my_real_domain.com

The second problem is a bit more complicated because you can’t do much about, the safest way to avoid copying email from website is using such or similar anchors:
< a href=”my_false_email@not_exisiting.com”>click to get my real email address< / a >

Also note that if you will use “mailto:” in href parameter, both of this techniques will NOT work at all, well i guess it is another downside of this method isn’t it?

Related posts:

1. Beginners guide to .htaccess file with examples – Part II
2. How does email really work
3. Increase upload file size in php using .htaccess

In this part, we will cover more examples with .htaccess file.

Presenting custom error pages

Use .htaccess file to present users with your custom pages for 401 [Authorization Required], 403 [Forbidden], 404 [not found] and 500 [Internal Server Error].

Syntax:
ErrorDocument < error-code > < location -of-custom-page>

Examples:
ErrorDocument 401 /401.html
ErrorDocument 403 /403.html
ErrorDocument 404 /404.html
ErrorDocument 500 /500.html

You can include some script in your customized pages to automatically send an email to you whenever those pages are called for. This way you will be notified every time a user encounters 404, 500 and other error messages.

Redirecting your-domain.com[non-www] to www.your-domain.com

From a search engine’s optimization point of view, we will use permanent redirection such that every time a request for non-www domain is made, it’s redirected and returns a status code of 301 [Permanent Redirect].

RewriteEngine On
RewriteCond %{HTTP_HOST} ^YourSite.com [nc]
RewriteRule (.*) http://www.YourSite.com/$1 [R=301,L]

In the above lines, the first line tells the RewriteEngine to be On, second line mentions the Rewrite Condition and the last one is the rewrite rule.

Limiting Number of simultaneous connections

To limit the number of simultaneous connections to a directory or your entire site, use the below line. If you place it in a directory other than the root directory, then it will limit the connections to that directory and its sub-directories only. Placing it in htaccess file of root directory will implement it for entire site.

Syntax:
MaxClients < number-of-connections>

Examples:
MaxClients 40
MaxClients 100

Allow/Disallow certain visitors from accessing your site

To accomplish it use the following lines. Look at the syntax first:

Syntax:
Order allow,deny
Deny from < incoming -address >
Allow from < incoming -address>

The first line [Order allow,deny] tells what should be done first. The second line tells about denying incoming-addresses [could be a single IP, an IP block, domain name and all] and third line tells about the incoming-addresses [could be a single IP, an IP block, domain name and all] those should be allowed. If second line has ‘Deny all’, then you should change the order of allow,deny in the first line to deny,allow.

To deny access to a single IP address and allow everyone else
Order allow,deny
Deny from 100.100.100.1
Allow from all

To deny a block of IP address and allow everyone else. [Notice the second line]
Order allow,deny
Deny from 100.100.100.
Allow from all

To deny a single IP address and allow everyone else. [Use it to block referrals from a specific domain]
Order allow,deny
Deny from www.my-domain.com
Allow from all

To deny everyone else but yourself. [Notice the order of allow,deny has changed in first line and also appending more 'Allow from' lines at the end, which is valid]

Order deny,allow
Deny from all
Allow from < your-ip-address >
Allow from < another-ip-address >
Allow from < www.domain.com>

Specify Administrator’s email address in error message

Using the line below in your htaccess file will display the conerned system administrator’s email address in the error messages. If you are not using custom pages for error messages, then this will help your visitors drop an email and let you know about problems.

Syntax:
ServerAdmin < a-valid-email-address>

Example:
ServerAdmin name@domain.com

I hope, that this tutorial will help you accomplish various tasks with ease. Your feedback, comments are welcome.

Related posts:

1. Beginners Guide to .htaccess File with Examples
2. Increase upload file size in php using .htaccess
3. Hide .php extension with url rewriting using .htaccess

There are several things that developers, site owners and webmasters can do by using .htaccess file. Let’s look at some of them:

• Prevent directory browsing
• Redirect visitors from one page or directory to another
• Password protection for directories
• Change the default index page of a directory
• Prevent hot-linking of images from your website

Since .htaccess file allows us to make changes on a per-directory basis, the following are valid places to put the .htaccess file in:

/.htaccess [placing in root folder of the site]
/content/.htaccess [placing in content folder]
/content/html/images/.htaccess [in the images folder]

Any command that you place in .htaccess file will affect it’s current directory where it is placed and also it’s sub-directories. You may put a .htaccess file in the root folder such that it will affect the whole site.

Make a backup of your .htaccess file [if you have any] before you attempt any of the settings mentioned in this article. I must not be held responsible for any consequences that arises due to editing your .htaccess file.

Working with .htaccess files

For creating and editing purpose, a normal text editor such as notepad will do. Alternatively, you can download a free copy of PSPad for easy editing. To be able to see files in your FTP software, you must enable settings in your FTP client to see hidden files on the remote server [applicable to your system as well]. When done editing, you can save the file with double quotes in windows. [Save file as ".htaccess", with double quotes]. This will save the file as .htaccess and will not prompt you for a file name as such. Let’s now move on to some common .htaccess file example.

Allow/Deny Directory Browsing

When directory browsing is on, people accessing a URL from your site with no index page or no pages at all, will see a list of files and folders. To prevent such directory access, just place the following line in your .htaccess file.

IndexIgnore */*

Many hosting companies, by default deny directory browsing and having said that, just in case you need to enable directory browsing, place the following line in your .htaccess file.

Options +Indexes

Redirect visitors from one page or directory to another

It’s quite simple. Look at the example lines below and place similar lines in your .htaccess file of the root folder and it will do the rest. [Remember to use permanent keyword in the line to tell the search engines that the old link has moved to the new link]. You can also setup multiple redirects using htaccess.

Syntax: Redirect permanent [old directory/file name][space][new directory/file name]

Redirect permanent /olddirectory /newdirectory
Redirect permanent /olddirectory /somedirectory/newdirectory
Redirect permanent /oldhtmlfile.htm /newhtmlfile.htm
Redirect permanent /oldhtmlfile.htm http://your-domain.com/newhtmlfile.htm

All the above lines are valid. Just remember to replace the file/directory names with actual ones.

Change the default index page of a directory or site

Almost every hosting company will have index.htm, index.html, index.php, index.asp, default.asp, default.html as the default index page names in their web server settings. So, in case your site ordirectory does not has a file name which matches a name from the list above, chances are that your visitors will either see a list of all the files and folders [throughdirectory browsing] or will not see anything at all. To change the default index page’s name for a directory or the site, place the following line in the .htaccess file of the root folder or the particular directory for which you want to change the index page’s name.

DirectoryIndex homepage.htm
DirectoryIndex somepage.htm

To have more names, put a space between file names and it will take into considerations all those file names as possible index page names. Which means, if it finds a filename matching a list of names you supplied [in the given order] in .htaccess, then it will open that page as the index page for thedirectory. The below line, with multiple names, is also a valid usage:

DirectoryIndex homapage.html somepage.html myindexpage.html anything.html

Remember, each entry must be in one line only.

Preventing hot linking of images from your website

If your website contains images which people from other websites are linking to and you get charged for the extra bandwidth, then placing the following lines willprevent any such image hot linking. Most of the hosting companies provide this feature in their control panel itself, such as CPanel. This trick requires mod_rewrite engine to be on in Apache on your web server.

RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?your-domain.com/.*$ [NC]
RewriteRule .(gif|jpg)$ – [F]

In the above code, replace [your-domain] with your actual domain name [without www], and instead of (www.\), use your actual subdomain name (sub-domain.\)

Prevent access to your .htaccess file (.htaccess security)

This article would remain incomplete without mentioning this trick. To prevent visitors from viewing your .htaccess file, place the following lines in your file. Of course, by default most Apache installations will not show .htaccess file but just in case.

<Files .htaccess>
order allow,deny
deny from all
</Files>

More information and detailed documentation, visit Apache website.

There’s also a second part to this tutorial – Beginners guide to .htaccess file with examples – Part II and you may also be interested in the Apache mod_rewrite examples for writing search engine friendly URLs.

Related posts:

1. change extension of web pages .php .html
2. Increase upload file size in php using .htaccess
3. How to make most out of Robots.txt File