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
-
Role of Robots.txt and Search Console parameters settings
Hi, wondering if anyone can point me to resources or explain the difference between these two. If a site has url parameters disallowed in Robots.txt is it redundant to edit settings in Search Console parameters to anything other than "Let Googlebot Decide"?
Technical SEO | | LivDetrick0 -
Robots.txt in subfolders and hreflang issues
A client recently rolled out their UK business to the US. They decided to deploy with 2 WordPress installations: UK site - https://www.clientname.com/uk/ - robots.txt location: UK site - https://www.clientname.com/uk/robots.txt
Technical SEO | | lauralou82
US site - https://www.clientname.com/us/ - robots.txt location: UK site - https://www.clientname.com/us/robots.txt We've had various issues with /us/ pages being indexed in Google UK, and /uk/ pages being indexed in Google US. They have the following hreflang tags across all pages: We changed the x-default page to .com 2 weeks ago (we've tried both /uk/ and /us/ previously). Search Console says there are no hreflang tags at all. Additionally, we have a robots.txt file on each site which has a link to the corresponding sitemap files, but when viewing the robots.txt tester on Search Console, each property shows the robots.txt file for https://www.clientname.com only, even though when you actually navigate to this URL (https://www.clientname.com/robots.txt) you’ll get redirected to either https://www.clientname.com/uk/robots.txt or https://www.clientname.com/us/robots.txt depending on your location. Any suggestions how we can remove UK listings from Google US and vice versa?0 -
Canonical tag for Home page: with or without / at the end???
Setting up canonical tags for an old site. I really need advice on that darn backslash / at the end of the homepage URL. We have incoming links to the homepage as http://www.mysite.com (without the backslash), and as http://www.mysite.com/ (with the backslash), and as http://www.mysite.com/index.html I know that there should be 301 redirects to just one version, but I need to know more about the canonical tags... Which should the canonical tag be??? (without the backslash) or (with the backslash) Thanks for your help! 🙂
Technical SEO | | GregB1230 -
The Mysterious Case of Pagination, Canonical Tags
Hey guys, My head explodes when I think of this problem. So I will leave it to you guys to find a solution... My root domain (xxx.com) runs on WordPress platform. I use Yoast SEO plugin. The next page of root domain -- page/2/ -- has been canonicalized to the same page -- page/2/ points to page/2/ for example. The page/2/ and remaining pages also have this rel tags: I have also added "noindex,follow" to page/2/ and further -- Yoast does this automatically. Note: Yoast plugin also adds canonical to page/2/...page/3/ automatically. Same is the case with category pages and tag pages. Oh, and the author pages too -- they all have self-canonicalization, rel prev & rel next tags, and have been "noindex, followed." Problem: Am I doing this the way it should be done? I asked a Google Webmaster employee on rel next and prev tags, and this is what she said: "We do not recommend noindexing later pages, nor rel="canonical"izing everything to the first page." (My bad, last year I was canonicalizing pages to first page). One of the popular blog, a competitor, uses none of these tags. Yet they rank higher. Others following this format have been hit with every kind of Google algorithm I could think of. I want to leave it to Google to decide what's better, but then again, Yoast SEO plugin rules my blog -- okay, let's say I am a bad coder. Any help, suggestions, and thoughts are highly appreciated. 🙂 Update 1: Paginated pages -- including category pages and tag pages -- have unique snippets; no full-length posts. Thought I'd make that clear.
Technical SEO | | sidstar0 -
I accidentally blocked Google with Robots.txt. What next?
Last week I uploaded my site and forgot to remove the robots.txt file with this text: User-agent: * Disallow: / I dropped from page 11 on my main keywords to past page 50. I caught it 2-3 days later and have now fixed it. I re-imported my site map with Webmaster Tools and I also did a Fetch as Google through Webmaster Tools. I tweeted out my URL to hopefully get Google to crawl it faster too. Webmaster Tools no longer says that the site is experiencing outages, but when I look at my blocked URLs it still says 249 are blocked. That's actually gone up since I made the fix. In the Google search results, it still no longer has my page title and the description still says "A description for this result is not available because of this site's robots.txt – learn more." How will this affect me long-term? When will I recover my rankings? Is there anything else I can do? Thanks for your input! www.decalsforthewall.com
Technical SEO | | Webmaster1230 -
• symbol in title tag
We have a few title tags with a circular dot symbol, which is created by the code "•" Humans see a dot, but googlebot sees • Does this negatively impact our SEO, or is googlebot aware that **• == *** to human eyes
Technical SEO | | lighttable0 -
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 -
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