There are times when is really necessary to change the way people get to your pages. If, for example, sometime in the past you wanted to bring people on a specific php page like, let’s say, ‘hello.php’ and now you want to bring them to ‘howareyou.php’, you make the file just as you want: howareyou.php. But what happens with those who in the past were visiting ‘hello.php’. Do you change the ‘hello.php’ file to look exactly as ‘howareyou.php’? That would be pointless. But nevertheless, you have to redirect the people to your new page. That is where the 301 redirect page comes into play.
So instead of writing the same content on ‘hello.php’ you go and write the following:
Why would you go and do that? Because the search engines will know that the page you’ve wrote in the past, are still on your site, but not in the same place; you just moved them permanently…
301 redirect is the most efficient and Search Engine Friendly method for webpage redirection. The code “301” is interpreted as “moved permanently“.
And now some quick and informative things about permanent redirects and chain redirections.
How to create a 301 Redirect – http://www.webconfs.com/how-to-redirect-a-webpage.php