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canonical URLs problem

8:19 am on Mar 6, 2007 (gmt 0)

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Over in the google forum I was told that there is a "canonical URL problem" with a site I am working on. From what I understand it is a problem because google thinks www.domain.com and domain.com are 2 different sites. One would think that google search would be smarter than that when it seems the same content on both sites.

Arennt 90% of websites setup with dual host headers on them without a redirect? So They are all wrong? So I should setup the domain .com website and put a 301 redirect from it to the www.domain.com site?

Thank you


11:55 am on Mar 6, 2007 (gmt 0)

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Setting up a 301 redirect is very easy so it's best to include this into your design as a safetly measure.

Personally, I have seen sites that have suffered tremendously because of canonical problems, and others that seem to get away with it.

Better safe than sorry in my opinion.


4:10 pm on Mar 6, 2007 (gmt 0)

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Does google have an article on this subject? Like i mentioend so many sites are setup this way and you would think that there woul dbe enough smarts built into the system


4:23 pm on Mar 6, 2007 (gmt 0)

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> They are all wrong?

Yes, they are. Many sites have different content on example.com, www.example.com, mobile.example.com, dev.example.com etc.

For instance, example.com might be the private corporate intranet for use by employees only, www.example.com might be the public Web site, and mobile.example.com might be a site specifically designed for mobile users, while dev.example.com might be a development server for testing changes to the site prior to release.

It is very expensive in terms of processing power to determine that the contents of two domains are the same. And it can easily become impossible if the sites contain dynamically-generated content, because the search engine would then have to account for content that changes based on the time of access, the geographic location of the requesting IP address, etc. And consider the case of a site that uses the current time to load schedule or weather information -- Determining that the supposedly-same page accessed through two different URLs at even split-second intervals might be impossible, becaue it would require the search engine to request both URLs at exactly the same time, and the server to serve them at exactly the same time -- the latter requirement being physically impossible.

Also, if you depend on the search engines to sort things out, you depend on their having enough time in their processing cycle to compare your various domains and subdomains -- something which is not at all a sure thing.

For best results, you should control all aspects of your site, and not depend on others -- It's your site, not theirs, and therefore in your best interest to run a tight ship.

There are many threads on this site dealing with domain and page-name canonicalization -- Use the search function to find the ones that apply to your situation. The available methods will vary based upon your server type -- e.g. Apache or IIS -- so include that in your search terms.