404 invalid URLS

[eluser]Unknown[/eluser]
Hi All,

I am new to codeigniter, and I have a problem for SEO duplicate content.

I have this URL: /categories/16/Suites however if I change the 16 to anything else, it still works.

Unfortunately for me i've been told this needs fixing!

Is there anyway I can check the category ID AND the text after it for a match in the categories? Same for product details. If the URL doesn't match, send the user to the 404 page.

Thanks in advance!

Dave