Web Page Redirects
Don't Lose Links and Visitors
When site structure and/or page names change, redirect traffic from old pages to new pages. Redirects help preserve the SEO value of external and internal links, improve user experience. Redirects send human and bot visitors to the correct page.
Provide a redirect for every old page that you delete. Someone, or some bot, may have linked to or indexed the page, and a redirect will help transfer the link authority to the new site.
Page Redirects' best use is correcting external links to your site (generally unchangeable), and as temporary internal measure Correct internal links, since redirects only pass partial "link juice" to the target page. It's the best practice.
Automated Link Testers like W3C Link Checker list broken links and redirects - correct both!
Windows Internet Information Server (IIS) and Apache Servers dominate the marketplace; the procedure for redirection differs by server type. Links to detailed guides are found below.
Apache "301" Page Redirects
A good guide to Apache redirects can be found here.
Windows Server Page Redirects
A good guide to Windows Server redirects can be found here.
When I first created the Sastrugi Marketing web site, I had a page called:
http://www.sastrugimarketing.com/searchengine.html
Later, I decided to use .php technology, so the page name changed to:
http://www.sastrugimarketing.com/searchengine.php
I used the following .htaccess redirect:
Redirect 301 /searchengine.html http://www.sastrugimarketing.com/searchengine.php
Still later, I decided to change the page name again, and used another redirect:
Redirect 301 /searchengine.php http://www.sastrugimarketing.com/search-engine
By pasting the original URL (http://www.sastrugimarketing.com/searchengine.html) into a Browser Address Bar, the chain of redirects leads to the current page. If any human or bot ever bookmarked, favorited, or indexed any of the pages, they'll be redirected to the current page.
However, every internal link should point at the latest URL. A small amount of page rank disappears with each redirect, and the potential for chaos with too many stacked redirects exists. A single code error in the .htaccess file, could unravel a chain of multiple redirects.
Redirects can be at the domain, subdomain, folder or page level; I've primarily discussed page redirects above.
Technically, the way I serve pages as Extensionless URLs is a redirect, but that's not really the type of redirect I'm talking about here.