Precedence of X-Robots-Tag header vs robots meta tag

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灰色年华
灰色年华 2021-02-14 00:34

I\'ve placed the following Header in my vhost config:

Header set X-Robots-Tag \"noindex, nofollow\"

The goal here is to just disab

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  • 2021-02-14 01:01

    Just an update to Dan's experience, I also have both the

    Header set X-Robots-Tag "noindex, nofollow"
    

    and

    <meta name="robots" content="index, follow" />
    

    on my one of my Wordpress sites, and a check in Google Search Console confirmed that the noindex in X-Robots-Tag is taking precedence as the pages have been crawled and but aren't indexed. So the logic in the correct answer is indeed, correct.

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  • 2021-02-14 01:12

    In my recent experience, when Google sees mixed-messages it prefers positive action by default - ie - it favours indexing - meanwhile will flag the issue as a critical error/warning in your webmaster tools console if you have one.

    see your site's status in google here: https://www.google.com/webmasters/

    see you site's status in bing here: http://www.bing.com/toolbox/webmaster (note that yahoo search is now powered by bing)

    Google takes this positive-by-default action because lots of site owners unwittingly have a dodgy cms semi-blocking robots and we know how google loves to accumulate as much data as it can - any excuse!

    if the technical settings are erroneous they're liable to be totally disregarded, and we know how search engines index and follow by default when no settings are specified.

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  • 2021-02-14 01:15

    I am not sure if a definitive answer can be given to the question, as the behavior may be implementation-dependent (on the robot side).

    However, I think there is reasonable evidence that X-Robots-Tag will take precedence over <meta name="robots" .... See :

    One significant difference between the X-Robots-Tag and the robots meta directive is:

    • X-Robots-Tag is part of the HTTP protocol header.
    • <meta name="robots" ... is part of the HTML document header.

    Therefore the the X-Robots-Tag belongs to HTTP protocol layer, while <meta name="robots" ... belongs to the HTML protocol layer.

    Protocol capture

    As they belong to a different protocol layer, they will not be parsed simultaneously by the (robot) client getting the page: The HTTP layer will be parsed first, and the HTML in a later step.

    (Also, it should be noted that X-Robots-Tag and <meta name="robots" ... are not suppported by all robots. Google and Yahoo/Bing suppport both, but according to this some support only <meta name="robots" ..., others support neither.)

    Summary :

    • if supported by the robot, X-Robots-Tag will be processed first ; restrictions (noindex, nofollow) apply (and <meta name="robots" ... is ignored).
    • else, <meta name="robots" ... directive applies.
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