How to Setup SEO Friendly 301 Redirect?

SEO Friendly 301 

The “301 Permanent Redirect” is the most efficient and search engine friendly method for redirecting websites. You can use it in several situations, including:

• to redirect an old website to a new address
• to setup several domains pointing to one website
• to enforce only one version of your website (www. or no-www)
• to harmonize a URL structure change

There are several ways to setup a 301 Redirect; below I will cover the most used ones:
PHP Single Page Redirect
In order to redirect a static page to a new address simply enter the code below inside the index.php file.
<?php
header("HTTP/1.1 301 Moved Permanently");
header("Location: http: // www . newdomain . com / page.html");
exit();
?>
PHP Canonical Redirect
The Canonical 301 Redirect will add (or remove) the www . prefixes to all the pages inside your domain. The code below redirects the visitors of the http: // domain . com version to http: // www. domain.com.
<?php
if (substr($_SERVER['HTTP_HOST'],0,3) != 'www') {
header('HTTP/1.1 301 Moved Permanently');
header('Location: http://www.'.$_SERVER['HTTP_HOST']
.$_SERVER['REQUEST_URI']);
}
?>
Apache .htaccess Singe Page Redirect
In order to use this method you will need to create a file named .htaccess (not supported by Windows-based hosting) and place it on the root directory of your website, then just add the code below to the file.
Redirect 301 /old/oldpage.htm /new/http : // www .domain. com/newpage.htm
Apache .htaccess Canonical Redirect
Follow the same steps as before but insert the code below instead (it will redirect all the visitors accessinghttp://domain.com/ to http://www.domain.com/)
Options +FollowSymlinks
RewriteEngine on
rewritecond %{http_host} ^domain.com [nc]
rewriterule ^(.*)$ http:// www . domain .com/$1 [r=301,nc]
ASP Single Page Redirect
This redirect method is used with the Active Server Pages platform.
<%
Response.Status="301 Moved Permanently"
Response.AddHeader='Location','http://www . new-url . com/'
%>
ASP Canonical Redirect

The Canonical Redirect with ASP must be located in a script that is executed in every page on the server before the page content starts.
<%
If InStr(Request.ServerVariables("SERVER_NAME"),"www") = 0 Then
Response.Status="301 Moved Permanently"
Response.AddHeader "Location","http://www."
& Request.ServerVariables("HTTP_HOST")
& Request.ServerVariables("SCRIPT_NAME")
End if
%>