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
-
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 -
Canonical Tag when using Ajax and PhantomJS
Hello, We have a site that is built using an AJAX application. We include the meta fragment tag in order to get a rendered page from PhantomJS. The URL that is rendered to google from PhantomJS then is www.oursite.com/?escaped_fragment= In the SERP google of course doesnt include the hashtag in the URL. So my question, with this setup, do i still need a canonical tag and if i do, would the canonical tag be the escaped fragment URL or the regular URL? Much Appreciated!
Technical SEO | | RevanaDigitalSEO0 -
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 -
Isnt it better to have headlines in H1 and H2 tags instead of p tags?
I am working with a simple site http://http://lightsigns.com/Uniko_Manufacturing_Limited.html They seek more SEO traffic. However, the two big headlines that read "Wholesale Supply to the Sign and Display Industries" which is on line 241 and 242 of the source code, its in a p tag, i.e. <p <span class="webkit-html-tag">style</p <span>="padding-top: 0pt; " class="paragraph_style_1">Wholesale Supply to the and <p <span class="webkit-html-tag">style</p <span>="padding-bottom: 0pt; " class="paragraph_style_1">Sign and Display Industries Likewise, the product titles are in p tags, also. For example, on the Slide-in Light Box product page, http://lightsigns.com/Slide_In_light_box.html , I have done keyword research and no one is using the words slide in light box.Plus, it is also a p tag, ie. line 43 reads style="padding-bottom: 0pt; padding-top: 0pt; " class="paragraph_style">Slide-in Light Box If I suggest that they make an H2 tag with SEO-optimized keywords such as Display Light Box - Slide-In LIght Box, would this indeed help SEO? In summary, is it correct to say that H1 and H2 tags are stronger signals to the search bots of what the page is about?
Technical SEO | | BridgetGibbons1 -
Allow or Disallow First in Robots.txt
If I want to override a Disallow directive in robots.txt with an Allow command, do I have the Allow command before or after the Disallow command? example: Allow: /models/ford///page* Disallow: /models////page
Technical SEO | | irvingw0 -
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 -
URL query strings and canonical tag
Hi, I have recently been getting my comparison website redesigned and developed onto wordpress and the site is now 90% complete. Part of the redesign has meant that there are now dynamic urls in the format: http://www.mywebsite.com/10-pounds-productss/?display=cost&value=10 I have other pages similar to this but with different content for the different price ranges and these are linked to from the menus: http://www.mywebsite.com/20-pounds-products/?display=cost&value=20 Now my questions are: 1. I am using Joost's All-in-one SEO plugin and this adds a canonical tag to the page that is pointing to http://www.mywebsite.com/10-pounds-products/ which is the permalink. Is this OK as it is or should i change this to http://www.mywebsite.com/10-pounds-products/?display=cost&value=10 2. Which URL will get indexed, what gets shown as the display URL in the SERPs and what page will users land on? I'm a bit confused so apologies if these seem like silly questions. Thanks
Technical SEO | | bizarro10000 -
Google Off/On Tags
I came across this article about telling google not to crawl a portion of a webpage, but I never hear anyone in the SEO community talk about them. http://perishablepress.com/press/2009/08/23/tell-google-to-not-index-certain-parts-of-your-page/ Does anyone use these and find them to be effective? If not, how do you suggest noindexing/canonicalizing a portion of a page to avoid duplicate content that shows up on multiple pages?
Technical SEO | | Hakkasan1