How to create a 301 redirect?

As described on URL Canonicalization article we published in March, having a unique URL ("canonicalization") for each webpage is important in improving your "Pagerank". Canonicalization is accomplished by redirecting non-standard webpages to a preferred ("standard") webpage. There are a number of ways to redirect a webpage, but 301 (HTTP/1.1 Status Code, "Moved Permanently") redirect is the search engine friendly method which passes the pagerank and search engine ranking status from old to a new page. Here is an examples of how 301 redirect can be implemented on LAMP (Linux/Apache/Mysql/PHP) environment.

PHP Redirect

<?php
Header( "HTTP/1.1 301 Moved Permanently" );
Header( "Location: http://www.new-url.com" );
?>

Apache .htaccess: non-www to www subdomain redirect

1. Make sure your httpd.conf file has the "Directory" directive with the "AllowOverride All" setting.

<Directory /path/to/your/domain/document/root>
    AllowOverride All
</directory>

2. Enable Mod-Rewirte Module

Your apache configuration should have the mod-rewrite module enabled, which is the default. You can verify this by perusing httpd.conf file for the following line:

LoadModule rewrite_module modules/mod_rewrite.so

3. Create a .htaccess file in the document root directory of your website with the following content.

RewriteEngine On
RewriteCond %{http_host} ^webtrafficexchange.com [nc]
RewriteRule ^(.*)$ http://www.webtrafficexchange.com/$1 [r=301,nc]

Just replace the "webtrafficexchange.com" with the domain name you're trying to redirect.