Those seo-savvy web programmers and search engine optimization specialists are familiar with the problem caused by changing a previously ranked url to a new url. For example, a page that a search engine has ranked on page 1 may be www.domainname.com/about/default.aspx . For a variety of reasons, it may be necessary to change the url to www.domainname.com/about-us/ . The new url will be identified by search engines as a new page, even though it is the same page. The PageRanking will be lower for the new "about-us" url and the "/about/default.aspx" url will drop its ranking. This is sometimes known as "Split PageRanking" and we want to solve this problem to optimize the page. Web designer, Jeff Sarmiento, summarizes the importance of avoiding split pageranking well.
There is a set of HTTP headers created at the top of each page, not displayed on the page. We can work with the response object to help optimize the new url and eliminate split-ranking. The best HTTP status code used for redirection is 301. This code communicates to search engines that the content is located elsewhere.
Content that follows the "Location: " code in the HTTP header is the new permanent location for the page. Utilizing the 301 status code help spiders and search engines get the message that the old URL is obsolete and should be replaced with the new URL. It also communicates to search engines that the ranking from the previous URL should be credited to the new one. The 301 status code is the most important status code for search engine optimization.
One way to resolve split page-ranking is redirecting with ASP.NET and IIS. Through ISAPI Rewrite you can use the 301 status code to permanently redirect the old url to the new url. It is an effective way of permanently redirecting an entire group of pages or redirecting urls one-by-one. A downfall is that ISAPI rewrite must be installed on the server. The ISAPI Rewrite method is not fully explained in this article. One company that offers an ISAPI rewrite tool covers this topic in-depth.
Another method is to create the permanent redirect, through code, dynamically on the page. For various reasons, some individual pages cannot be generalized in an ISAPI rule. It is still essential to give search engines the message that the url has been permanently redirected. You can manipulate the response headers using the Response object provided by the current HttpContext object in ASP.NET
The HTTP header on the example at the top of this article would be
Location: http://www.domainname.com/about-us/
Utilizing the location code along with the 301 status code effectively achieves the permanent redirect.
Below is the code for permanently redirecting the example url we used above:
C#
if (Request.Path == "/about/default.aspx")
{
Response.Status = "301 Moved Permanently";
}
VB
if Request.Path = "/about/default.aspx" then
Response.Status = "301 Moved Permanently"
Response.AddHeader("Location", "http://www.example.com/about-us/")
end
In summary, it is a good idea to use the HTTPContext object and the 301 status code to communicate to search engines that a page has permanently been moved. This optimizes the page by crediting the pageranking from the previous url to the new url. It is a way of eliminating split-PageRanking effects by changing the url of an exiting page.
Happy Optimizing!