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.
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
-
One domain - Multiple servers
Can I have the root domain pointing to one server and other URLs on the domain pointing to another server without redirecting, domain masking or HTML masking? Dealing with an old site that is a mess. I want to avoid migrating the old website to the new environment. I want to work on a page by page and section by section basis, and whatever gets ready to go live I will release on the new server while keeping all other pages untouched and live on the old server. What are your recommendations?
Intermediate & Advanced SEO | May 9, 2017, 8:58 AM | Joseph-Green-SEO0 -
Googlebot being redirected but not users?
Hi, We seem to have a slightly odd issue. We noticed that a number of our location category pages were slipping off 1 page, and onto page 2 in our niche. On inspection, we noticed that our Arizona page had started ranking in place of a number of other location pages - Cali, Idaho, NJ etc. Weirdly, the pages they had replaced were no longer indexed, and would remain so, despite being fetched, tweeted etc. One test was to see when the dropped out pages had been last crawled, or at least cached. When conducting the 'cache:domain.com/category/location' on these pages, we were getting 301 redirected to, you guessed it, the Arizona page. Very odd. However, the dropped out pages were serving 200 OK when run through header checker tools, screaming frog etc. On the face of it, it would seem Googlebot is getting redirected when it is hitting a number of our key location pages, but users are not. Has anyone experienced anything like this? The theming of the pages are quite different in terms of content, meta etc. Thanks.
Intermediate & Advanced SEO | Jun 13, 2017, 5:55 AM | Sayers0 -
Setting A Custom User Agent in Screaming Frog
Hi all, Probably a dumb question, but I wanted to make sure I get this right. How do we set a custom user agent in Screaming Frog? I know its in the configuration settings, but what do I have to do to create a custom user agent specifically for a website? Thanks much! Malika
Intermediate & Advanced SEO | Jul 23, 2016, 4:27 PM | Malika10 -
Will I lose Link Juice when implementing a Reverse Proxy?
My company is looking at consolidating 5 websites that it has running on magento, wordpress, drupal and a few other platforms on to the same domain. Currently they're all on subdomains but we'd like to consolidate the subdomains to folders for UX and SEO potential. Currently they look like this: shop.example.com blog.example.com uk.example.com us.example.com After the reverse proxy they'll look like this: example.com/uk/ example.com/us/ example.com/us/shop example.com/us/blog I'm curious to know how much link juice will be lost in this switch. I've read a lot about site migration (especially the Moz example). A lot of these guides/case studies just mention using a bunch of 301's but it seems they'd probably be using reveres proxies as well. My questions are: Is a reverse proxy equal to or worse/better than a 301? Should I combine reverse proxy with a 301 or rel canonical tag? When implementing a reverse proxy will I lose link juice = ranking? Thanks so much! Jacob
Intermediate & Advanced SEO | Mar 21, 2016, 5:27 PM | jacob.young.cricut0 -
Best way to remove full demo (staging server) website from Google index
I've recently taken over an in-house role at a property auction company, they have a main site on the top-level domain (TLD) and 400+ agency sub domains! company.com agency1.company.com agency2.company.com... I recently found that the web development team have a demo domain per site, which is found on a subdomain of the original domain - mirroring the site. The problem is that they have all been found and indexed by Google: demo.company.com demo.agency1.company.com demo.agency2.company.com... Obviously this is a problem as it is duplicate content and so on, so my question is... what is the best way to remove the demo domain / sub domains from Google's index? We are taking action to add a noindex tag into the header (of all pages) on the individual domains but this isn't going to get it removed any time soon! Or is it? I was also going to add a robots.txt file into the root of each domain, just as a precaution! Within this file I had intended to disallow all. The final course of action (which I'm holding off in the hope someone comes up with a better solution) is to add each demo domain / sub domain into Google Webmaster and remove the URLs individually. Or would it be better to go down the canonical route?
Intermediate & Advanced SEO | Sep 6, 2017, 3:07 PM | iam-sold0 -
Best server-side sitemap generators
I've been looking into sitemap generators recently and have got a good knowledge of what creating a sitemap for a small website of below 500 URLs involves. I have successfully generated a sitemap for a very small site, but I’m trying to work out the best way of crawling a large site with millions of URLs. I’ve decided that the best way to crawl such a large number of URLs is to use a server side sitemap, but this is an area that doesn’t seem to be covered in detail on SEO blogs / forums. Could anyone recommend a good server side sitemap generator? What do you think of the automated offerings from Google and Bing? I’ve found a list of server side sitemap generators from Google, but I can’t see any way to choose between them. I realise that a lot will depend on the type of technologies we use server side, but I'm afraid that I don't know them at this time.
Intermediate & Advanced SEO | Dec 13, 2013, 5:49 PM | RG_SEO0 -
Server Migration, Does it effect SEO?
About to go through a server migration. My intitial thought is that a change in servers shouldn't really change my rankings. But I've heard rumors... Can a server migration change rankings? Why?
Intermediate & Advanced SEO | Sep 10, 2012, 8:10 PM | Thos0030 -
Changing Server IP Addresses. Should I be concerned?
Hello Mozers Our site has been on a dedicated server for about four years now. (no other sites, just ours on the server) I have made the decision to move it to a much better and faster server than the current server we are on for more than one reason. My big fear is Google will lose trust for my site because of the IP change. Ip's stay with the server at 1and1 they do not follow the website. So, I have done my due diligence and copied over all code and databases and have tested it completely to insure there are no issues when I change the DNS to point to the new server. Made sure 1and1 is giving me an IP that has never been used, I am Keeping the old server on until cached DNS records expire for it. Is there anything else I need to do to make sure I do not lose current rankings in Google? I have heard nightmare stories about making these kinds of changes but at this point for our site there is no turning back this is a change that must take place. Any pointers and advice would be much appreciated! Thanks!
Intermediate & Advanced SEO | Aug 3, 2012, 4:47 AM | Robbie82991