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TechnologyOct 31, 2011

Use Permanent Redirects to Minimally Impact SEO

Joshua Grear

I recently had the pleasure of working with a great team of individuals to rebrand our company’s public website (www.credera.com) using SharePoint 2010.    As a part of the rebranding effort, the organization and amount of content changed significantly compared to the previous site.  For this reason, we were faced with a small challenge that carried with it a potentially large negative impact.  With most, if not all, of our inbound links being broken, how do we retain our hard earned page ranking?

The answer is to leverage 301 permanent redirects.  A 301 permanent redirect tells the requestor, in our case the search engine, that the content has permanently moved and that they need to update their records.  Although the concept of redirection is simple, the implementation can sometimes be tricky.  With that in mind, I will describe a few of the common approaches and the steps necessary to accomplish a sound SEO strategy.

Client-Side vs. Server Side

Redirection can be configured on either the client (browser) or the server.  While client-side scripting can provide redirection capabilities, it will not aid us in terms of SEO as search engine spiders often ignore client-side scripting.  It is for that reason that I will focus only on server-side redirection.

Types of Server-Side Redirection

There are two basic types of server-side redirection, code-based and server-based.  Code-based redirection relies on the existence of the page that you wish to have redirect to a new location.  Server-based redirection, on the other hand, relies on the web server to interrogate incoming requests and determine if redirection is necessary.  Since we do not wish to maintain the existing site content over time, we chose to implement redirection through IIS using the URL Rewrite Module.

Implementation

Redirection implementation will vary greatly from project to project.  Each project has a unique set of constraints and variables to consider.  However, there are a few key steps that always must be considered.

1) Content Mapping

This first, and probably the most critical, step is to define where each request is to be redirected to.  The best way to accomplish this is to first take an inventory of the pages on the current site.  Next, identify where in the new site the user should be redirected to if they request that resource.

2) Identify Request Patterns

Once you have a comprehensive mapping from old to new content, you will want to start identifying patterns.  Ideally you will be able to identify a few key patterns that will cover most cases.  Using the IIS URL Rewrite Module, you will have the following types of pattern matching options:

  • Exact Match – matches the input exactly

  • Wildcards – matches the input with the use of wildcards

  • Regular Expressions – matches the input using regular expressions

3) Configure the Rewrite Module

Finally, when all mapping scenarios are covered by defined patterns, you will configure the Rewrite Module to redirect to the new locations.  The order the rules are executed in is important, so ensure that more generic rules/patterns are defined last.

Next Steps

If you are faced with the task of reorganizing or removing content from an existing site, I would highly recommend considering the impact to SEO.  Failure to do so could result in a drop in your page rank on search engines.  Credera has many thought leaders in the SEO space and would love to help you analyze, strategize and/or implement the perfect SEO strategy for you.