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:
Got a burning SEO question?
Subscribe to Moz Pro to gain full access to Q&A, answer questions, and ask your own.
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
-
Robots.txt allows wp-admin/admin-ajax.php
Hello, Mozzers!
Technical SEO | | AndyKubrin
I noticed something peculiar in the robots.txt used by one of my clients: Allow: /wp-admin/admin-ajax.php What would be the purpose of allowing a search engine to crawl this file?
Is it OK? Should I do something about it?
Everything else on /wp-admin/ is disallowed.
Thanks in advance for your help.
-AK:2 -
Disallow wildcard match in Robots.txt
This is in my robots.txt file, does anyone know what this is supposed to accomplish, it doesn't appear to be blocking URLs with question marks Disallow: /?crawler=1
Technical SEO | | AmandaBridge
Disallow: /?mobile=1 Thank you0 -
Duplicate title while setting canonical tag.
Hi Moz Fan, My websites - https://finance.rabbit.co.th/ has run financial service, So our main keywords is about "Insurance" in Thai, But today I have an issues regarding to carnonical tag. We have a link that containing by https://finance.rabbit.co.th/car-insurance?showForm=1&brand_id=9&model_id=18&car_submodel_id=30&ci_source_id=rabbit.co.th&car_year=2014 and setting canonical to this url - https://finance.rabbit.co.th/car-insurance within 5,000 items. But in this case I have an warning by site audit tools as Duplicate Page Title (Canonical), So is that possible to drop our ranking. What should we do, setting No-Index, No-Follow for all URL that begin with ? or keep them like that.
Technical SEO | | ASKHANUMANTHAILAND0 -
Robots txt. in page with 301 redirect
We currently have a a series of help pages that we would like to disallow from our robots txt. The thing is that these help pages are located in our old website, which now has a 301 redirect to current site. Which is the proper way to go around? 1- Add the pages we want to disallow to the robots.txt of the new website? 2- Break the redirect momentarily and add the pages to the robots.txt of the old one? Thanks
Technical SEO | | Kilgray0 -
Block Domain in robots.txt
Hi. We had some URLs that were indexed in Google from a www1-subdomain. We have now disabled the URLs (returning a 404 - for other reasons we cannot do a redirect from www1 to www) and blocked via robots.txt. But the amount of indexed pages keeps increasing (for 2 weeks now). Unfortunately, I cannot install Webmaster Tools for this subdomain to tell Google to back off... Any ideas why this could be and whether it's normal? I can send you more domain infos by personal message if you want to have a look at it.
Technical SEO | | zeepartner0 -
Should I include tags in sitemap?
Hello All, I was wondering if you should include tags and categories in your sitemap. In the past on previous blogs I have always left tags and categories out. The reason for this is a good friend of mine who has been doing SEO for a long time and inhouse always told me that this would result in duplicate content. I thought that it would be a great idea to get some input from the SEOmoz community as this obviously has a big affect on your blog and the number of pages indexed. Any help would be great. Thanks, Luke Hutchinson.
Technical SEO | | LukeHutchinson1 -
Do I need to add canonical link tags to pages that I promote & track w/ UTM tags?
New to SEOmoz, loving it so far. I promote content on my site a lot and am diligent about using UTM tags to track conversions & attribute data properly. I was reading earlier about the use of link rel=canonical in the case of duplicate page content and can't find a conclusive answer whether or not I need to add the canonical tag to these pages. Do I need the canonical tag in this case? If so, can the canonical tag live in the HEAD section of the original / base page itself as well as any other URLs that call that content (that have UTM tags, etc)? Thank you.
Technical SEO | | askotzko1 -
Is blocking RSS Feeds with robots.txt necessary?
Is it necessary to block an rss feed with robots.txt? It seems they are automatically not indexed (http://googlewebmastercentral.blogspot.com/2007/12/taking-feeds-out-of-our-web-search.html) And, google says here that it's important not to block RSS feeds (http://googlewebmastercentral.blogspot.com/2009/10/using-rssatom-feeds-to-discover-new.html) I'm just checking!
Technical SEO | | nicole.healthline0