Here is a short intro on how to make sure that major search engines (Google, Yahoo, Microsoft) can be directed to see different URLs with the same content as a single ‘conanical’ URL. For example, the following links point to the same page but have different URLs

• http://nu.edu.pk/default.aspx
• http://nu.edu.pk
• http://www.nu.edu.pk/default.aspx
• http://www.nu.edu.pk/
• http://nu.edu.pk/default.ASPX

The solution is to select a single point as your representative URL and include this line in the HTML code.

Although a standard 301 redirect should work too, but this would be a bit easier for the non-techie designers and SEO enthusiasts to implement.