In the September 2017 survey we received responses from 1,805,060,730 sites and 6,798,101 web-facing computers, reflecting a gain of 4.49 million sites and 84,800 computers. This is the largest number of web-facing computers in history, and cloud computing has helped fuel this growth considerably. The top three cloud hosting providers—Amazon, Alibaba and DigitalOcean—now account for nearly 22% of all web-facing computers, as well as more than a third of this month's net computer growth.

nginx has dominated this month's computer growth once again, with an additional 49,900 computers taking its market share up to 22.2%. This puts it within 20,000 computers of Microsoft's 22.5% share, giving nginx a realistic chance of taking second place by next month. Meanwhile, Apache remains far ahead in the lead with 2.88 million web-facing computers giving it a 42.3% share of the market.

While more than half of the websites in the survey are using Microsoft web server software, relatively few of these are active sites. Discounting link farms, domain holding pages and other automatically generated content, Microsoft accounts for only 7.3% of all active sites, while Apache leads with 44.9%, and nginx follows with 20.7%. Microsoft's active sites share has never exceeded Apache's, and ever since it peaked at 38% in early 2009, it has experienced a general decline.

Microsoft's presence within the top million websites has also been steadily declining – in 2008, it had a 20% share, but this has since dwindled to less than 10%. Today, 9.73% of the top million sites use Microsoft web server software (mostly IIS – Internet Information Services), while Apache leads with 38.9%. However, Apache has also been experiencing a general decline since 2011, while nginx has continued to muscle its way in. A further 1,299 nginx-powered sites made their way into the top million this month, lifting nginx's share to 29.4%.

Web-facing operating systems

Apache has been the most commonly installed web server for many years, but which underlying operating systems are used by the world's web facing computers?

By far the most commonly used operating system is Linux, which runs on more than two-thirds of all web-facing computers. This month alone, the number of Linux computers increased by more than 91,000; and again, this strong growth can largely be attributed to cloud hosting providers, where Linux-based instances are typically the cheapest and most commonly available.

It is difficult to distinguish different Linux distributions by examining their TCP/IP characteristics, but inferences can be made from other clues, such as Server headers. The Linux distribution can be positively identified in around 30% of cases, and of these 1.39 million Linux computers, just over half are running Ubuntu Linux, nearly a quarter are running CentOS, and around fifth are running Debian Linux.

Microsoft is next up, with 26.8% of all web-facing computers running various versions of Windows Server. Interestingly, this is higher than Microsoft's web server share (22.5%), and can be explained by around 20% of Windows computers being used to run other web server software – such as Apache and nginx – rather than its native Microsoft IIS web server. Conversely, around 51,000 Linux computers expose Microsoft IIS web servers to the internet – in these cases, the Linux frontends are typically acting as load balancers or reverse proxies to backend Windows computers running IIS.

Windows Server 2008 is the most commonly used version of the Windows Server family of operating systems – it currently runs on 971,000 web-facing computers, and this is followed by Windows Server 2012, which is installed on 505,000.

Windows and Linux are essentially the "big two" when it comes to web-facing operating systems. FreeBSD was once notorious for its reliability and impressively large uptimes when used as a server platform; indeed, Netcraft's infrastructure made extensive use of it in the past, but it is now a relatively niche operating system compared with its heyday. Today it is used by only 1.3% of web-facing computers, more than half of which are being used to run the Apache web server.

In the May 2017 survey we received responses from 1,814,996,345 sites and 6,404,290 web-facing computers. Although the total number of sites has fallen slightly, by 1.4 million since April, the number of computers has grown by 83,000.

Large shifts in site counts

Although it fared well in other metrics (see below), nginx suffered a massive 30% loss of hostnames this month. With a net loss of more than 100 million sites, its market share has fallen by 5.71 percentage points to 13.5%. The majority of the sites that disappeared were Chinese-language spam sites hosted at Amazon Web Services in the United States and Japan.

Meanwhile, Microsoft gained 79 million sites, which has taken its market share up to 49.1%. This is Microsoft's highest market share in the 22-year history of the Web Server Survey, and also reflects a significant change in fortunes over the past year: Last June, Apache had the largest market share of websites, but now Microsoft's share is more than twice as large as Apache's, which fell by a further 1.73 percentage points this month to 20.95%.

nginx leads active site growth

Despite the large loss of hostnames, nginx gained nearly a million active sites, which has taken its active sites share back above 20%. This suggests most of the 104 million hostnames it lost did not have distinct content, and therefore were of little interest to ordinary web users, despite the apparent size of the change.

Apache continues to lead the active sites market quite comfortably with a 45.6% share, although a loss of 1.4 million active sites has brought this down by 0.67 percentage points. nginx stays firmly in second place, with more than twice as many active sites as Microsoft.

nginx's computer growth continues unabated

nginx's consistent computer growth has continued, making it look ever more likely to overtake Microsoft later in 2017. Its gain of 48,500 computers – combined with Microsoft's loss of 6,000 – has reduced the difference in their market shares by nearly a whole percentage point.

nginx is now within 3.46 percentage points of Microsoft's share of 23.8%; but Apache also maintains a comfortable lead in this market – it increased its web-facing computer count by 28,800 this month, keeping Apache's share above 43%.

nginx pushing others out of the top million

nginx is also continuing to make strong progress amongst the top million websites, where it has been ahead of Microsoft for the past few years. It was the only major vendor to increase its presence this month, resulting in thousands of competing vendors' websites being pushed out of the top million. Apache suffered most, with 3,200 Apache-powered sites departing the top million, but it still leads this market with a 40.5% presence.

Apache has exhibited a slow and steady decline over the past several years. Coupled with nginx's consistent growth within the top million sites, the gap between the two is ever decreasing; however, it looks like it will be a good year or two until nginx seriously starts to threaten Apache's lead.

New nginx 1.13 mainline branch

nginx 1.13.0 was released on 25th April. This is the first release on the new, actively-developed 1.13.x mainline branch, adding bugfixes and new features to what was essentially the most recent stable version of nginx (1.12.0).

The most notable new feature in nginx 1.13.0 is its support for TLS 1.3, which aims to be the latest and most secure version of the Transport Layer Security protocol – although not many underlying crypto libraries actually offer TLS 1.3 yet. The TLS 1.3 specification has not yet been finalised, although the working draft has been sufficient for some servers and clients to implement it. For example, Mozilla's NSS cryptographic library – which is used by Firefox – enables TLS 1.3 support by default.

Microsoft IIS Administration API enters general availability

The Microsoft IIS Administration API that we mentioned in February is now Generally Available. The newest 1.1.0 release also facilitates management of the IIS Central Certificate Store, and includes an improved certificate API. These features are intended to make it easier to manage certificates across entire farms of web servers.

LiteSpeed enters the Amazon cloud

LiteSpeed Technologies is now a Technology Partner in the Amazon Web Services Partner Network (APN), coinciding with the release of the LiteSpeed Web Server AMI. This Amazon Machine Image is based on CentOS 7 with the LiteSpeed Web Server pre-installed. AWS users can now use this AMI to quickly deploy ready-to-use virtual machines that run the LiteSpeed Web Server in the cloud.

This month's Web Server Survey found 6.4 million websites running LiteSpeed, which encompasses 2.3 million active sites, more than 2 million unique domain names, and nearly 11,000 web-facing computers. One of the busiest sites currently using LiteSpeed is FanFiction.Net, which is an automated fan fiction archive.

Enter the Beaver

China saw a large number of new sites being served by the relatively unknown "Beaver" web server. Just over a million sites now exhibit the Beaver Server header, and these make use of more than 110,000 unique domain names – mostly under the .cn top-level domain. Most of the sites are hosted by Aliyun, which is China's largest cloud hosting provider, while the majority of the rest are hosted by other Chinese companies. Only a single Beaver site is hosted outside of China – this solitary instance is hosted in Japan, at Amazon's Tokyo AWS region.

The behaviour of these sites suggests that Beaver might not be an entirely new web server, but possibly an application based on Microsoft's HTTP Server API (HTTPAPI 2.0). This API lets C/C++ programmers receive HTTP requests and send responses without using Microsoft IIS. At least 38 million other websites also use HTTPAPI 2.0.

But most of the Beaver sites are currently inaccessible and display the following message: "According to the filing requirements of China's Ministry of Industry and Information Technology (MIIT), the website is accessible only if the ICP information is accurate and the ICP license is filed". An ICP Filing ("Bei'an") is required by all content providers in China before they can use hosting and CDN products, but this only allows them to be used for informational purposes. A Commercial ICP Licence ("Zheng") is required for any website that sells goods or services that directly generate revenue online.

Pepyaka making the web more friendly

The little-known Pepyaka web server has also been quietly growing. This server is used predominantly by Wix, an Israeli company that provides a friendly website building platform to millions of users. Wix provides free website hosting under the *.wix.com domain, or customers can get a free custom domain name when upgrading to one of Wix's yearly premium plans.

This business model has led to a high ratio of domains to hostnames amongst the Pepyaka install base. Wix-hosted websites alone account for 1.4% of all unique domain names in use on the web, which is no mean feat. All of these sites are hosted within the Amazon Web Services cloud, using Pepyaka version 1.11.3. This version number, coupled with Wix's previous uses of nginx, suggests that it could be based on last year's mainline version of nginx.

In the April 2017 survey we received responses from 1,816,416,499 sites and 6,320,910 web-facing computers. This reflects a gain of 56 million sites and 49,800 computers.

Microsoft had a noticeable gain of 108 million sites (+15.4%), recouping last month's loss and expanding its market share by nearly 5 percentage points to 44.7%. Microsoft is 10 million sites down from the start of the year, but its share is now nearly twice as large as Apache's. The only major vendor to suffer a loss of hostnames in April was nginx, which lost 1.4 million sites – this took its market share down by 0.41 points to 19.2%, leaving it slightly further behind Apache's share of 22.7%.

Despite nginx's loss of sites, it was once again the only major vendor to increase its presence within the top million sites, increasing its count by 2,164 sites, while Apache lost 1,962; but Apache stays in the lead with a 40.9% share, while nginx's increased to 28.7%.

nginx's growth is also reflected well in the web-facing computers market, where it had the largest increase of 29,900 computers (+2.44%). This took its share up by 0.32 points to 19.9%, while Apache's leading share fell by 0.27 points to 43.5%. Microsoft is still in second place with 24.2% of the web-facing computer market, but this position looks set to be taken by nginx within the next year if the trend of nginx's gains and Microsoft's losses continue.

Apache continues to reign supreme in terms of active sites, where it increased its market share slightly to 46.3%, putting it further ahead of nginx, which has a share of 19.6%; however, the long term trend over the past several years has seen the two vendors getting closer, with nginx slowly gaining market share while Apache has slowly declined. Microsoft's share of active sites is only 8.28%, but this is enough to keep it in third place, ahead of Google.

A new mainline version of nginx (1.11.13) was released on 4 April. This release included several bugfixes and formed the basis of the current stable version, nginx 1.12.0, which was later released on 12 April. As a consequence of including all bug fixes and new features from the entire 1.11.x branch, nginx 1.12.0 includes support for configuring multiple SSL certificates of different types, better support for dynamic modules, and several other new features.

Earlier this month, Netcraft examined the success of ICANN's New gTLD program, as well as the impact it has had on brand owners such as LEGO. The .loan gTLD saw the largest domain growth of any type of TLD this month, gaining 287,000 unique domains, yet losing more than 10 million websites. Only 3% of all .loan domains are considered active by Netcraft, indicating that large numbers share near-identical content, such as monetized domain holding pages.

From the TLD operator's perspective, the rise in .loan domains is much more significant than the large reduction in sites, as each unique domain will correspond to a domain registration, which invariably involves some type of transaction. The cost of registering a single .loan domain can vary between $20-$40 per year (including ICANN fees), depending which registrar is used, although some registrars – such as Namecheap – offer low introductory prices of $0.88 for the first year only. The prevalence of domain holding pages suggests that many of these domains may have been bought at introductory prices, so the estimated revenue from the 980,000 unique .loan domains currently in use on the web is likely to be much closer to $1m than $40m.