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
-
Do Canonical Tags Pass Link Juice?
I have an ecommerce website where some pages link to a product page with a different URL. EXAMPLE: 1: /category/product1.html (not indexed by Google) with canonical pointing to product1.html Other page link to the product like below. 2: product1.html (indexed by Google) Now the question is, does 1: pass any link juice to product1.html or not? Is it worth to change everything and link only to one URL? My site is running on Magento!
Technical SEO | | bill3690 -
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 -
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 -
Do H2 tags carry more weight than h4 tags?
Of course H tags are key signals for relevance in search. Does an h2 tag send a significantly "louder" signal than an h4 tag?
Technical SEO | | aj6130 -
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 -
How do I fix the h1 tag?
No More Than One H1 Tag Easy fix <dl> <dt>Number of H1s</dt> <dd>2</dd> <dt>Explanation</dt> <dd>Best practices for both SEO and accessibility require only a single H1 tag. The H1 is meant to be the page's headline, and thus, multiple H1s are confusing. Consider employing H2, H3 or CSS styles to achieve the same results with text visualization.</dd> <dt>Recommendation</dt> <dd>Remove multiple instances of the H1 tag, so that only one exists on the page.</dd> <dd>I get this error yet it does not tell me how to fix it. I'm not even sure what the H1 tag is?
Technical SEO | | 678648631264
</dd> </dl>0 -
Geotargeting duplicate content to different regions - href and canonical tag confusion
If you duplicate content onto a sub-folder for say a new US geotargeted site (to target kw spelling differences) and, in addition to GWT geotargeting settings, implement the 'Canonical' and 'Hreflang' tags on these new pages to show G different region and language version (en-us). Then does the original/main site similar pages also need to have canonical and href tags ? The main/original sites page I don't really want to target a specific country (although existing signals (hosting etc) will be UK (primary target of main site) but pages show up in other country searches too (which we want). Im presuming fine to leave the original/main site as it currently is although wording in google blog/webmaster central articles etc are a bit confusing hence why im asking for anyone elses opinion/input on this. Also is there are any benefit (or just best practice) to use 'www.example.com/en-us/...' in the subdirectory URL as opposed to just 'www.example.com/us/' many thanks in advance to any commentators 🙂
Technical SEO | | Dan-Lawrence0 -
Robots.txt file getting a 500 error - is this a problem?
Hello all! While doing some routine health checks on a few of our client sites, I spotted that a new client of ours - who's website was not designed built by us - is returning a 500 internal server error when I try to look at the robots.txt file. As we don't host / maintain their site, I would have to go through their head office to get this changed, which isn't a problem but I just wanted to check whether this error will actually be having a negative effect on their site / whether there's a benefit to getting this changed? Thanks in advance!
Technical SEO | | themegroup0