Pitfalls when implementing the “VARY User-Agent” server response
-
We serve up different desktop/mobile optimized html on the same URL, based on a visitor’s device type.
While Google continue to recommend the HTTP Vary: User-Agent header for mobile specific versions of the page (http://www.youtube.com/watch?v=va6qtaiZRHg), we’re also aware of issues raised around CDN caching; http://searchengineland.com/mobile-site-configuration-the-varies-header-for-enterprise-seo-163004 / http://searchenginewatch.com/article/2249533/How-Googles-Mobile-Best-Practices-Can-Slow-Your-Site-Down / http://orcaman.blogspot.com/2013/08/cdn-caching-problems-vary-user-agent.html
As this is primarily for Google's benefit, it's been proposed that we only returning the Vary: User-Agent header when a Google user agent is detected (Googlebot/MobileBot/AdBot).
So here's the thing: as the server header response is not “content” per se I think this could be an okay solution, though wanted to throw it out there to the esteemed Moz community and get some additional feedback.
You guys see any issues/problems with implementing this solution?
Cheers!
linklater
-
So, there are lots of 'ifs' here, but the primary problem I see with your plan is that the CDN will return the content to Googlebot without the request hitting your server so you won't have the option to serve different headers to Googlebot.
Remember that every page is the main HTML content (which may be static or dynamically generated for every request), and then a whole bunch of other resources (Javascript and CSS files, images, font files etc.). These other resources are typically static and lend themselves far better to being cached.
Are your pages static or dynamic? If they are dynamic then you are possibly not benefitting from them being cached anyway, so you could use the 'vary' header on just these pages, and not on any static resources. This would ensure your static resources are cached by your CDN and give you a lot of the benefit of the CDN, and only the dynamic HTML content is served directly from the server.
If most of your pages are static you could still use this approach, but just without the full benefit of the CDN, which sucks.
Some of the CDNs are already working on this (see http://www.computerworld.com/s/article/9225343/Akamai_eyes_acceleration_boost_for_mobile_content and http://orcaman.blogspot.co.uk/2013/08/cdn-caching-problems-vary-user-agent.html) to try and find better solutions.
I hope some of this helps!
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
-
Duplicate without user-selected canonical excluded
We have pdf files uploaded in the media of wordpress and used in our website. As these pdfs are duplicate content of the original publishers, we have marked links to these pdf urls as nofollow. These pages are also disallowed in robots.txt Now, Google Search Console has shown these pages Excluded as "Duplicate without user-selected canonical" As it comes out we cannot use canonical tag with pdf pages so as to point to the original pdf source If we embed a pdf viewer in our website and fetch the pdfs by passing the urls of the original publisher, would the pdfs be still read as text by google and again create duplicate content issue? Another thing, when the pdf expires and is removed, it would lead to 404 error. If we direct our users to the third party website, then it would add up to our bounce rate. What should be the appropriate way to handle duplicate pdfs? Thanks
Intermediate & Advanced SEO | | dailynaukri1 -
Title tag and user intent
I am just wondering if I create a page that present different e-bike kits and my title tag tag is "the best e-bike kits in 2019", will I rank on "e-bike kits" and "best e-bike kits" or on just "best e-bike kits" ? It seems that user intent can be tricky and sometimes a title tag can make all the difference. How about if I write "Explore Burgundy on a bike tour "to rank on "Burgundy bike tour", will I rank or is the user intent different when I write explore (meaning I am looking for something self guided instead of guided) Thank you,
Intermediate & Advanced SEO | | seoanalytics0 -
SEO Benefit to Hosting Site on a Dedicated Server?
Our annual hosting plan expires soon. Our website is hosted on a shared server. Is there an SEO benefit to hosting our site on a dedicated server. Could this result in faster download times which is a ranking factor? Our traffic is currently low (only about 20 visits per day). Thanks!!
Intermediate & Advanced SEO | | Kingalan1
Alan0 -
Should I implement Structure Data Markup before implementing AMP?
I am about to implement AMP and structured data markup on my site which one should be done first?
Intermediate & Advanced SEO | | Leebi0 -
Domain remains the same IP address is changing on same server only last 3 digits changing. Will this effect rankings
Dear All, We have taken and a product called webacelator from our hosting UKfast and our ip address is changing. UKFasts asked to point DNS to different IP in order to route the traffic through webacelator, which will enhance browsing speed. I am concerned, will this change effect our rankings. Your responses highly appreciated.
Intermediate & Advanced SEO | | tigersohelll0 -
After Server Migration - Crawling Gets slow and Dynamic Pages wherein Content changes are not getting Updated
Hello, I have just performed doing server migration 2 days back All's well with traffic moved to new servers But somehow - it seems that w.r.t previous host that on submitting a new article - it was getting indexed in minutes. Now even after submitting page for indexing - its taking bit of time in coming to Search Engines and some pages wherein content is daily updated - despite submitting for indexing - changes are not getting reflected Site name is - http://www.mycarhelpline.com Have checked in robots, meta tags, url structure - all remains well intact. No unknown errors reports through Google webmaster Could someone advise - is it normal - due to name server and ip address change and expect to correct it automatically or am i missing something Kindly advise in . Thanks
Intermediate & Advanced SEO | | Modi0 -
Enormous 7 page drop after switching servers and adding load balancers. Thoughts?
Hello Everyone, I'm a longtime Moz user but I had to switch accounts after switching jobs. I was hoping someone might be able to give me some insight on whats going on if possible. Our startup had first page position for our most valuable keyword: "Crowdfunding real estate" for about 6 or 7 months. Once we launched and switched to a production server behind load balancers, we dropped almost overnight to 7th page and we've been there for about a month. We don't have many links yet and some of the ones we DO have are kind of spammy (no idea where they came from and in process of trying to get them removed) but we thought it'd be strange to see that massive drop. We are even pages below a competitor who has NO links and basically zero content on the page. We don't have any notifications in WMT about a manual penalty or anything. I'd really, really appreciate any advice and If anyone has any ideas, the page is at: PatchofLand.com Thanks, Jason
Intermediate & Advanced SEO | | PatchofLand0 -
Implementation of AJAX Crawling Specifications
My URL is: http://www.redfin.com/TX/Austin/8413-Navidad-Dr-78735/home/31224372 We're using Google's AJAX crawling system, per the documentation here. https://developers.google.com/webmasters/ajax-crawling/The example page above requires JavaScript to display content; it includes in the source. We have a lot of pages like this on our site.We expect Google to query us at this URL:http://www.redfin.com/TX/Austin/8413-Navidad-Dr-78735/home/31224372?escaped_fragment=This page renders correctly with JavaScript disabled.Are we doing this correctly? There are some small differences between the escaped_fragment HTML snapshot and the JavaScript-generated content. Will this cause any problems for us?We ask because there was a period of about two months (from October 4th to Dec 29th) during which Google's crawler radically decreased the hits to our escaped_fragment URLs; it's maybe recovering now, but maybe it isn't, and I wanted to be absolutely sure we're doing this correctly.
Intermediate & Advanced SEO | | RyanOD0