PHP Version: 5.3.3
Joomla Version: 2.5.8
Artio Joomsef Version: 4.2.9

I'm having lately a lot of problems with duplicated content.

The problem is that the duplicated content Google is showing me in the webmaster tool isn't linked from the website and often the duplicated content url is "index.php?some-var" so the duplicated content url is a NON-SEF url.
I did run Xenu on the website so I'm sure that the wrong url isn't linked from the website.

I fear that someone of my competitor is trying to penalize my website telling google to index some of my webpages passing the article id but with many different itemid or catid.

I would like to know how Artio works with NON-SEF Url with the wrong Itemid or wrong catid. I did run some test and I saw that if I use the NON-SEF Url associated with the SEF Url Artio will just redirect me to the SEF Url but when I tried to change from the NON-SEF Url the catid or the itemid I saw some strange behavior.

I know this shouldn't be an issue since the links are not present in the website and then Google shouldn't index them but since I'm finding many of them being indexed I need to find a solution.

Hi,

Unfortunately, Joomla doesn't handle this very well, as it doesn't force components to check their input variables.

JoomSEF should redirect you to the SEF URL when you change only the Itemid if you have the "Ignore multiple sources" option enabled. Other than that it's not currently possible in Joomla to check whether the Itemid is correct.

But for other variables (like catid), their values should be checked by their corresponding components.
In paid version of JoomSEF you can use Variables Filtering to set up rules for variables values to filter out non-sense data, but it can't handle the case where catid is just replaced with different number.

If you're interested, we can customize your Joomla's Content component to check its input variables and handle the situations when the data are incorrect (either by redirecting to correct page or showing the 404 error) as a paid support service.

Thanks for the answer, I would be interested in the customization of the Content component.
How much would it cost?
And will it be then an official release meaning that with the future upgrade of the Content component I will not loose the feature?

We wouldn't be modifying JoomSEF but core Joomla's Content component, so you would lose the modifications if you updated your Joomla in the future.

I estimate the time required for implementation is 5 hours. For pricing please see www.artio.net/e-shop/support-services

Also please note that this would only prevent duplicate content for your articles, as only the Content component would be modified. So duplicate content with other components would still be possible (for example Newsfeeds, Weblinks or other components you have installed). Fixing all the components could be quite time consuming.

Would you be able to put all the modification to a section of the Joomla content component so I can copy them when I upgrade Joomla?

I understand this wouldn't work with a major upgrade of the component but I guess that could work with little update.

We could put as much code as possible to a new file and mark the modifications in existing files with comments like: