Moz Q&A is closed.
After more than 13 years, and tens of thousands of questions, Moz Q&A closed on 12th December 2024. Whilst we’re not completely removing the content - many posts will still be possible to view - we have locked both new posts and new replies. More details here.
Robots.txt and canonical tag
-
In the SEOmoz post - http://www.seomoz.org/blog/robot-access-indexation-restriction-techniques-avoiding-conflicts, it's being said -
If you have a robots.txt disallow in place for a page, the canonical tag will never be seen.
Does it so happen that if a page is disallowed by robots.txt, spiders DO NOT read the html code ?
-
Thanks Ryan for explaining things very clearly.
-
What we know is there have been many cases where a page that is blocked in robots.txt has appeared in search results. The explanation provided is that robots.txt blocks crawlers during normal site visits, but not necessarily on visits where they are following links from other sites.
-
If spiders follow links to an article on my site, will they read the contents then ? If the canonical tag is on article page itself, will canonical tag will be seen ?
-
Daylan offered a great answer but I would like to add one exception. When crawlers from the major SEs visit your site they will honor your robots.txt file but sometimes they will follow links from other sites to an article on your site, and during that particular visit they will not see the robots.txt file and index your page.
This is one of the reasons why your robots.txt file should be used as minimally as possible, and when it is used you should have a backup process in place such as the canonical or noindex tag on a page.
-
Thanks Daylan for your quick response. I just wanted a second opinion that canonical tag will never be seen if a page is disallowed.
-
Thats correct in most cases:
It works likes this: a robot wants to vists a Web site URL, say http://www.example.com/welcome.html. Before it does so, it firsts checks for http://www.example.com/robots.txt, and finds:
User-agent: *
Disallow: /The "User-agent: *" means this section applies to all robots. The "Disallow: /" tells the robot that it should not visit any pages on the site.
Robots can ignore your /robots.txt. Especially malware robots that scan the web for security vulnerabilities, and email address harvesters used by spammers will pay no attention.
More information available here about:
Browse Questions
Explore more categories
-
Moz Tools
Chat with the community about the Moz tools.
-
SEO Tactics
Discuss the SEO process with fellow marketers
-
Community
Discuss industry events, jobs, and news!
-
Digital Marketing
Chat about tactics outside of SEO
-
Research & Trends
Dive into research and trends in the search industry.
-
Support
Connect on product support and feature requests.
Related Questions
-
Dynamic Canonical Tag for Search Results Filtering Page
Hi everyone, I run a website in the travel industry where most users land on a location page (e.g. domain.com/product/location, before performing a search by selecting dates and times. This then takes them to a pre filtered dynamic search results page with options for their selected location on a separate URL (e.g. /book/results). The /book/results page can only be accessed on our website by performing a search, and URL's with search parameters from this page have never been indexed in the past. We work with some large partners who use our booking engine who have recently started linking to these pre filtered search results pages. This is not being done on a large scale and at present we only have a couple of hundred of these search results pages indexed. I could easily add a noindex or self-referencing canonical tag to the /book/results page to remove them, however it’s been suggested that adding a dynamic canonical tag to our pre filtered results pages pointing to the location page (based on the location information in the query string) could be beneficial for the SEO of our location pages. This makes sense as the partner websites that link to our /book/results page are very high authority and any way that this could be passed to our location pages (which are our most important in terms of rankings) sounds good, however I have a couple of concerns. • Is using a dynamic canonical tag in this way considered spammy / manipulative? • Whilst all the content that appears on the pre filtered /book/results page is present on the static location page where the search initiates and which the canonical tag would point to, it is presented differently and there is a lot more content on the static location page that isn’t present on the /book/results page. Is this likely to see the canonical tag being ignored / link equity not being passed as hoped, and are there greater risks to this that I should be worried about? I can’t find many examples of other sites where this has been implemented but the closest would probably be booking.com. https://www.booking.com/searchresults.it.html?label=gen173nr-1FCAEoggI46AdIM1gEaFCIAQGYARS4ARfIAQzYAQHoAQH4AQuIAgGoAgO4ArajrpcGwAIB0gIkYmUxYjNlZWMtYWQzMi00NWJmLTk5NTItNzY1MzljZTVhOTk02AIG4AIB&sid=d4030ebf4f04bb7ddcb2b04d1bade521&dest_id=-2601889&dest_type=city& Canonical points to https://www.booking.com/city/gb/london.it.html In our scenario however there is a greater difference between the content on both pages (and booking.com have a load of search results pages indexed which is not what we’re looking for) Would be great to get any feedback on this before I rule it out. Thanks!
Technical SEO | | GAnalytics1 -
Robots.txt Syntax for Dynamic URLs
I want to Disallow certain dynamic pages in robots.txt and am unsure of the proper syntax. The pages I want to disallow all include the string ?Page= Which is the proper syntax?
Technical SEO | | btreloar
Disallow: ?Page=
Disallow: ?Page=*
Disallow: ?Page=
Or something else?0 -
Is there a limit to how many URLs you can put in a robots.txt file?
We have a site that has way too many urls caused by our crawlable faceted navigation. We are trying to purge 90% of our urls from the indexes. We put no index tags on the url combinations that we do no want indexed anymore, but it is taking google way too long to find the no index tags. Meanwhile we are getting hit with excessive url warnings and have been it by Panda. Would it help speed the process of purging urls if we added the urls to the robots.txt file? Could this cause any issues for us? Could it have the opposite effect and block the crawler from finding the urls, but not purge them from the index? The list could be in excess of 100MM urls.
Technical SEO | | kcb81780 -
Rel=canonical Weebly
My problem is with my website as it says I have duplicate page titles and contents because of a /index.html. It says the duplicate content is due to the fact that my homepage on my website is www.seacandytackle.com but it is also www.seacandytackle.com/index.html because I use weebly. How can I use the tag to fix this? It won't let me do a 301 redirect because it is a home page. How can I fix this? What code would I have to use and which url? Also it says that I have duplicate page content between http://www.seacandytackle.com/index.html and http://www.seacandytackle.comhttp://www.seacandytackle.com but I don't recall having any page that looks like http://www.seacandytackle.com http://www.seacandytackle.com from weebly. How can I fix this issue as well? Thank you for any help. Step by step implementation would be particularly helpful in using the rel= tags to fix these duplicate issues.
Technical SEO | | SeaCandyTackle0 -
Duplicate title-tags with pagination and canonical
Some time back we implemented the Google recommendation for pagination (the rel="next/prev"). GWMT now reports 17K pages with duplicate title-tags (we have about 1,1m products on our site and about 50m pages indexed in Google) As an example we have properties listed in various states and the category title would be "Properties for Sale in [state-name]". A paginated search page or browsing a category (see also http://searchengineland.com/implementing-pagination-attributes-correctly-for-google-114970) would then include the following: The title for each page is the same - so to avoid the duplicate title-tags issue, I would think one would have the following options: Ignore what Google says Change the canonical to http://www.site.com/property/state.html (which would then only show the first XX results) Append a page number to the title "Properties for Sale in [state-name] | Page XX" Have all paginated pages use noindex,follow - this would then result in no category page being indexed Would you have the canonical point to the individual paginated page or the base page?
Technical SEO | | MagicDude4Eva2 -
No indexing url including query string with Robots txt
Dear all, how can I block url/pages with query strings like page.html?dir=asc&order=name with robots txt? Thanks!
Technical SEO | | HMK-NL0 -
Does Bing ignore robots txt files?
Bonjour from "Its a miracle is not raining" Wetherby Uk 🙂 Ok here goes... Why despite a robots text file excluding indexing to site http://lewispr.netconstruct-preview.co.uk/ is the site url being indexed in Bing bit not Google? Does bing ignore robots text files or is there something missing from http://lewispr.netconstruct-preview.co.uk/robots.txt I need to add to stop bing indexing a preview site as illustrated below. http://i216.photobucket.com/albums/cc53/zymurgy_bucket/preview-bing-indexed.jpg Any insights welcome 🙂
Technical SEO | | Nightwing0 -
Should there be a canonical tag on my 404 error page?
In my crawl diagnostics, I notice some 4xx client errors. They are appearing for pages that no longer exist, so I'm not sure what the problem is. Shouldn't they just be dealt as 404's? Anyway, on closer inspection I noticed that my 404 error page contains a canonical tag which points to the missing page. Could this be the issue? Is it a good idea to remove the canonical tag from this error page? Thanks.
Technical SEO | | Leighm0