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
-
How long does it take for canonical tags to work
How long on average does it take for a canonical tag to work? Understand that canonicals are just a suggestion, but after adding a canonical tag and submitting the page via Google fetch, assuming Google follows the canonical, would you expect it to work after a day or two or does it take longer? We added canonicals to old PPC landing pages that are ranking organically, though our new landing pages (which we want to rank organically) are not identical and have a bit more content/features. They are similar though. Canonicals were added to the old pages (pointing to new pages) and requested indexing via search console. Old pages are still ranking and new pages not so much. FYI we are unable to 301 old PPC pages due to other non negotiable reasons unfortunately. Thanks.
Technical SEO | | SoulSurfer80 -
Do URLs with canonical tags get indexed by Google?
Hi, we re-branded and launched a new website in February 2016. In June we saw a steep drop in the number of URLs indexed, and there have continued to be smaller dips since. We started an account with Moz and found several thousand high priority crawl errors for duplicate pages and have since fixed those with canonical tags. However, we are still seeing the number of URLs indexed drop. Do URLs with canonical tags get indexed by Google? I can't seem to find a definitive answer on this. A good portion of our URLs have canonical tags because they are just events with different dates, but otherwise the content of the page is the same.
Technical SEO | | zasite0 -
Removing a canonical tag from Pagination pages
Hello, Currently on our site we have the rel=prev/next markup for pagination along with a self pointing canonical via the Yoast Plugin. However, on page 2 of our paginated series, (there's only 2 pages currently), the canonical points to page one, rather than page 2. My understanding is that if you use a canonical on paginated pages it should point to a viewall page as opposed to page one. I also believe that you don't need to use both a canonical and the rel=prev/next markup, one or the other will do. As we use the markup I wanted to get rid of the canonical, would this be correct? For those who use the Yoast Plugin have you managed to get that to work? Thanks!
Technical SEO | | jessicarcf0 -
Can I set a canonical tag to an anchor link?
I have a client who is moving to a one page website design. So, content from the inner pages is being condensed in to sections on the 'home' page. There will be a navigation that anchor links to each relevant section. I am wondering if I should leave the old pages and use rel=canonical to point them to their relevant sections on the new 'home' page rather than 301 them. Thoughts?
Technical SEO | | Vizergy0 -
I need help with a PHP canonical URL tags
I found a little difficult for me to do a canonical tag in my PHP. On-Page Report Card We check to make sure that IF you use canonical URL tags, it points to the right page. If the canonical tag points to a different URL, engines will not count this page as the reference resource and thus, it won't have an opportunity to rank. If you've not made this page the rel=canonical target, change the reference to this URL. NOTE: For pages not employing canonical URL tags, this factor does not apply. I don't know how to tidy my PHP Any suggestion.
Technical SEO | | lnietob0 -
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 -
Can I Disallow Faceted Nav URLs - Robots.txt
I have been disallowing /*? So I know that works without affecting crawling. I am wondering if I can disallow the faceted nav urls. So disallow: /category.html/? /category2.html/? /category3.html/*? To prevent the price faceted url from being cached: /category.html?price=1%2C1000
Technical SEO | | tylerfraser
and
/category.html?price=1%2C1000&product_material=88 Thanks!0 -
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