Hi wilsonn. To prevent canonical issues on your site you need to choose a preferred version. Google treat www and non www as two separate URL's. To select a preferred domain you must add and verify www and non www in webmaster tools. There after you can 301 redirect the non-prefered version to the preferred version. Remember to submit a sitemap with the preferred version URL,s and the same would apply to your pages. On site canonical in the head section of your document is for pages that are similar or duplicate. This will tell Google which is the original document, preventing copy issues and perhaps penalties. rel=canonical is used in the head section of your document and it points to the preferred version. Let's take a look at an example..... If your preferred version is home.com then you need to tell Google its the preferred version by adding a link element with the attribute rel="canonical" to the head section of the non-canonical version, which in this case would be home.com/copy. So you would add the following to the head section of home.com/copy. link rel="canonical" href="http://home.com"/ You are now pointing to the preferred version which is naturally home.com. And you can also add the same to the head section of home.com so that it points to itself link rel="canonical" href="http://home.com"/ telling Google that is the preferred version. So basically you need to point to the preferred version. Regards, knysna.
When your website opens with www and non-www is known as canonical error. It can be fix through .htaccess file.
Canonical URL is basically used for product based site that have same URL with differed ID. So in order to reduce duplication you need canonicalization. Eg:- 1. domainname/catagory/77 2. domainname/catagory/88 In order to remove duplication till category canonical URLs are used.