Canonical Tag as 302 Resolution in Google
26th August 2009 by Kerry Dye
So what happens when you have a CMS that has lots of 302s in place that you can’t change to 301 redirects? Apart from tearing your hair out that is?
Well, as I had this situation, I thought I would try using the canonical meta tag to see what would happen. The situation I had was this:
www.domainname.com/friendly-url
302 redirected to
www.domainname.com/non-friendly-url
So from a SERPs clickthrough point of view, I did want the friendly version to rank, and it also was the ranking page for some terms. Both versions were visible in the index in a site: search.
So what is the problem with a 302?
A 302 redirect tells the search engines that the page has moved but only temporarily. This results in both versions of the page being indexed, which of course is duplicate content.
Now, Google has never been that bad about making sure that one version is given a higher priority, but if you have a lot of these, it does mean you have a lot of pages on your site that are lesser valued (and would have been supplemental, when it existed). But the problem exists that both page names may get links created to them, and then Google has more of an issue with which one is the “right” version – the canonical version as the SEO lingo goes.
Potential Pitfalls
As we hadn’t tested this technique before, my concern was that you could get a cyclical effect going on i.e. the 302 saying look at the non-friendly page and the canonical tag saying look at the 302’d page.
So what happened using the canonical meta tag?
Exactly the right thing really, from my point of view. The non-friendly version has disappeared from the index, and the friendly version has increased its ranking by a couple of places for some key search terms.
So you can use the canonical meta tag to resolve duplicate content issues caused by 302 redirects.
Kerry Dye
Campaign Delivery Manager
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