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
-
ALT tags - How important are they?
I realise ALT tags are important from an accessibility perspective but in terms of organic search, do they carry much value? I have a big site and it doesn't look like ALT tags have been added generally, it would be a massive job to fix and I'm just trying to weigh up what to concentrate on first. Does anybody have any real life experience?
Technical SEO | | seoman100 -
Should a login page for a payroll / timekeeping comp[any be no follow for robots.txt?
I am managing a Timekeeping/Payroll company. My question is about the customer login page. Would this typically be nofollow for robots?
Technical SEO | | donsilvernail0 -
Canonical Tags on Parameter Pages With Hreflang
Hey Everyone: We are currently implementing hreflang tags on our site, and we have many parameter pages with hreflang tags; however, I am afraid these may be counted as duplicate content without canonical tags. example.com/utm_source=tpi href='http://example.com/de" hreflang="de" rel="alternate" href='http://example.com/nl" hreflang="nl" rel="alternate" href='http://example.com/fr" hreflang="fr" rel="alternate" href='http://example.com/it" hreflang="it" rel="alternate" I have two questions 1. Do I need a canonical tag pointing to example.com ? 2. On the homepage without the parameter, should I add self referencing hreflang tags? (href="http://example.com/" hreflang="es" Thanks so much for your help! Kyle
Technical SEO | | TeespringMoz0 -
Do I have a robots.txt problem?
I have the little yellow exclamation point under my robots.txt fetch as you can see here- http://imgur.com/wuWdtvO This version shows no errors or warnings- http://imgur.com/uqbmbug Under the tester I can currently see the latest version. This site hasn't changed URLs recently, and we haven't made any changes to the robots.txt file for two years. This problem just started in the last month. Should I worry?
Technical SEO | | EcommerceSite0 -
Google indexing despite robots.txt block
Hi This subdomain has about 4'000 URLs indexed in Google, although it's blocked via robots.txt: https://www.google.com/search?safe=off&q=site%3Awww1.swisscom.ch&oq=site%3Awww1.swisscom.ch This has been the case for almost a year now, and it does not look like Google tends to respect the blocking in http://www1.swisscom.ch/robots.txt Any clues why this is or what I could do to resolve it? Thanks!
Technical SEO | | zeepartner0 -
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 -
How can I make Google Webmaster Tools see the robots.txt file when I am doing a .htacces redirec?
We are moving a site to a new domain. I have setup an .htaccess file and it is working fine. My problem is that Google Webmaster tools now says it cannot access the robots.txt file on the old site. How can I make it still see the robots.txt file when the .htaccess is doing a full site redirect? .htaccess currently has: Options +FollowSymLinks -MultiViews
Technical SEO | | RalphinAZ
RewriteEngine on
RewriteCond %{HTTP_HOST} ^(www.)?michaelswilderhr.com$ [NC]
RewriteRule ^ http://www.s2esolutions.com/ [R=301,L] Google webmaster tools is reporting: Over the last 24 hours, Googlebot encountered 1 errors while attempting to access your robots.txt. To ensure that we didn't crawl any pages listed in that file, we postponed our crawl. Your site's overall robots.txt error rate is 100.0%.0 -
How does robots.txt affect aliased domains?
Several of my sites are aliased (hosted in subdirectories off the root domain on a single hosting account, but visible at www.theSubDirectorySite.com) Not ideal, I know, but that's a different issue. I want to block bots from viewing those files that are accessible in subdirectories on the main hosting account, www.RootDomain.com/SubDirectorySite/, and force the bots to look at www.SubDirectorySite.com instead. I utilized the canonical meta tag to point bots away from the sub directory site, but I am wondering what will happen if I use robots.txt to block those files from within the root domain. Will the bots, specifically Google bot, still index the site at its own URL, www.AnotherSite.com even if I've blocked that directory with Disallow: /AnotherSite/ ? THANK YOU!!!
Technical SEO | | michaelj_me0