<rel canonical="">and Query Strings</rel>

[Yun]

How are you supposed to <rel canonical="" tag="">a page with a query string that has already been indexed? It's not like you're serving that page from a CMS where you have an original page with content to add to the head tag.</rel>

For example....

Original Page = http://www.example.com/about/products.php

Query String Page = http://www.example.com/about/products.php?src=FrontDoorBox

Would adding the <rel canonical="" tag="">to the original page, referencing itself, be the solution so that the next time the original page is crawled, the bot will know that the previously indexed URL with query string should actually be the "original"? That's the only solution I can come up with because there's no way to find the query string rendered page to tag with the canonical.....</rel>

[RyanKent]

The page being indexed already is not a factor. You want to add the tag to the primary page and all variant pages with parameters. The next time those pages are crawled, Google will see the canonical tag and adjust the URL accordingly.

Your question is difficult because the answer would depend on how your CMS is coded.

Generally there is a template which is used to create the pages. Your template would need to be modified using a conditional statement to provide the canonical tag for URLs with parameters. This would be your best solution.