When a search engine spider indexes a website, it gathers as much information about the website as possible. This may also include the IP address. Why is that a problem? Well for starters, if you have multiple domain names under one IP address, the search engine could possibly label one of the websites as duplicate content. This may not always happen, but it is important to remember that search engines are primarily composed of robots and may overlook simple mistakes that can easily be detected by an average human.

Duplicate Content

Duplicate content posts many issues for search engine crawlers. Search engines rarely show duplicate content on their results pages. Crawlers are forced to choose which content out of the duplicates is the original (unless you tell it otherwise). This could affect the website in many ways and in the worst case, the website may not show up in the search engine results page at all. Therefore, having a search engine mistakenly label your website as duplicate content can be a problem if it is not fixed. There are several reasons why this might happen; mostly due to the way search engine algorithms have been programmed to process and index websites.

Canonicalization And SEO

From an SEO point of view, canonicalization is very important. If you have a website that has the same content spread across different URLs, search engines will split the rankings as well. An example is typing a website without the www in the toolbar – this effectively dilutes your presence on the web.

Typing in the website link with or without the www at beginning will still lead you to the same website, however search engines may process this differently. This issue can be fixed by creating redirects. There are three main types of redirect methods: the 301, 302 and 307 redirect.

301 Redirect And IP Canonicalization

The main objective of fixing IP canonicalization is to redirect the webpages that could possibly be labeled as duplicate content or webpages back to the original URL to make sure the IP address does not get indexed. One solution is to create a 301 redirect. A 301 redirect is a permanent redirect from one URL to another. This is very similar to a change in postal address at the post office. There are no search engine penalties involved when dealing specifically with 301 redirects as oppose to other types of redirects.

The best way on a *NIX server to set up a 301 redirect is to edit the .htaccess file found in the root directory. The code to input in the .htaccess file when setting up a 301 redirect is the following:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^xxx.xxx.xxx.xxx [nc,or]
RewriteCond %{HTTP_HOST} ^example.com [nc]
RewriteRule (.*) http://www.example.com/$1 [R=301,L]

All you have to do is replace the xxx with the IP address and example with the domain name. This method of redirecting as a solution for IP Canonicalization is simple yet very effective when applied properly. For an extra preventive measure, you may also choose to edit the robots.txt file of the website to block specific parts from being indexed.

It is essential to note that after applying a 301 redirect, some websites tend to experience a decrease in traffic for a few weeks. It is also important to update the Sitemap.xml file when implementing any changes to the website such as a 301 redirect.