Editing Web server (section)

=== Explosive growth and competition (1996–2014) ===
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|caption=Number of active web sites (1996-2002)<ref name="ws-stats-1991-1996"/><ref name="ws-stats-1999-2002">{{cite web |url=https://news.netcraft.com/archives/2021/12/22/december-2021-web-server-survey.html |title=Web Server Survey, NOTE: number of active web sites in year 2000 has been interpolated |publisher=Netcraft |author= |date=22 December 2021 |access-date=2021-12-27 |archive-date=27 December 2021 |archive-url=https://web.archive.org/web/20211227070918/https://news.netcraft.com/archives/2021/12/22/december-2021-web-server-survey.html |url-status=live }}</ref>
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[[File:Cobalt Qube 3 Front.jpg|thumb|right|Sun's [[Cobalt Qube]] 3 – a computer [[server appliance]] (2002, discontinued)]]
At the end of 1996, there were already over '''fifty''' known (different) web server software programs that were available to everybody who wanted to own an Internet [[domain name]] and/or to host websites.<ref name="ws-1996-sw-products">{{Cite web |url=http://www.netcraft.com/survey/servers.html |title=Netcraft: web server software (1996) |author= |publisher=Netcraft (web archive) |access-date=2021-12-16 |archive-url=https://web.archive.org/web/19961230090855/http://www.netcraft.com/survey/servers.html |archive-date=30 December 1996 |url-status=dead}}</ref> Many of them lived only shortly and were replaced by other web servers.

The publication of [[Request for Comments|RFC]]s about protocol versions HTTP/1.0 (1996) and HTTP/1.1 (1997, 1999), forced most web servers to comply (not always completely) with those standards.  The use of TCP/IP [[HTTP persistent connection|persistent connection]]s (HTTP/1.1) required web servers both to increase the maximum number of concurrent connections allowed and to improve their level of scalability.

Between 1996 and 1999, [[Netscape Application Server|Netscape Enterprise Server]] and Microsoft's IIS emerged among the leading commercial options whereas among the freely available and [[open-source]] programs Apache HTTP Server held the lead as the preferred server (because of its reliability and its many features).

In those years there was also another commercial, highly innovative and thus notable web server called [[Zeus Web Server|Zeus]] (''now discontinued'') that was known as one of the fastest and most scalable web servers available on market, at least till the first decade of 2000s, despite its low percentage of usage.

Apache resulted in the most used web server from mid-1996 to the end of 2015 when, after a few years of decline, it was surpassed initially by IIS and then by Nginx. Afterward IIS dropped to much lower percentages of usage than Apache (see also [[#Market share|market share]]).

From 2005–2006, Apache started to improve its speed and its scalability level by introducing new performance features (e.g. event MPM and new content cache).<ref name="ws-apache-overview-2.2">{{Cite web|url=https://httpd.apache.org/docs/2.2/new_features_2_2.html|title=Overview of new features in Apache 2.2|publisher=Apache: HTTPd server project|year=2005|access-date=2021-12-16|language=en|archive-date=27 November 2021|archive-url=https://web.archive.org/web/20211127091204/http://httpd.apache.org/docs/2.2/new_features_2_2.html|url-status=live}}</ref><ref name="ws-apache-overview-2.4">{{Cite web|url=https://httpd.apache.org/docs/2.4/new_features_2_4.html|title=Overview of new features in Apache 2.4|publisher=Apache: HTTPd server project|year=2012|access-date=2021-12-16|language=en|archive-date=26 November 2021|archive-url=https://web.archive.org/web/20211126112829/http://httpd.apache.org/docs/2.4/new_features_2_4.html|url-status=live}}</ref> As those new performance improvements initially were marked as experimental, they were not enabled by its users for a long time and so Apache suffered, even more, the competition of commercial servers and, above all, of other open-source servers which meanwhile had already achieved far superior performances (mostly when serving static content) since the beginning of their development and at the time of the Apache decline were able to offer also a long enough list of well tested advanced features.

In fact, a few years after 2000 started, not only other commercial and highly competitive web servers, e.g. [[LiteSpeed Web Server|LiteSpeed]], but also many other open-source programs, often of excellent quality and very high performances, among which should be noted [[Hiawatha (web server)|Hiawatha]], [[Cherokee (webserver)|Cherokee HTTP server]], [[Lighttpd]], [[Nginx]] and other derived/related products also available with commercial support, emerged.

Around 2007–2008, most popular web browsers increased their previous default limit of 2 persistent connections per host-domain (a limit recommended by RFC-2616)<ref name="rfc2616-8.1.4">{{cite IETF |rfc=2616 |sectionname=Connections, persistent connections: practical considerations |section=8.1.4|title=RFC 2616, Hypertext Transfer Protocol -- HTTP/1.1|pages=46–47}}</ref> to 4, 6 or 8 persistent connections per host-domain, in order to speed up the retrieval of heavy web pages with lots of images, and to mitigate the problem of the shortage of persistent connections dedicated to dynamic objects used for bi-directional notifications of events in web pages.<ref name="browsers-max-persistent-connections-per-host-domain">{{Cite web|url=http://sgdev-blog.blogspot.com/2014/01/maximum-concurrent-connection-to-same.html|title=Maximum concurrent connections to the same domain for browsers|author=|publisher=|year=2017|access-date=2021-12-21|archive-date=21 December 2021|archive-url=https://web.archive.org/web/20211221234815/http://sgdev-blog.blogspot.com/2014/01/maximum-concurrent-connection-to-same.html|url-status=live}}</ref> Within a year, these changes, on average, nearly tripled the maximum number of persistent connections that web servers had to manage. This trend (of increasing the number of persistent connections) definitely gave a strong impetus to the adoption of [[reverse proxy|reverse proxies]] in front of slower web servers and it gave also one more chance to the emerging new web servers that could show all their speed and their capability to handle very high numbers of concurrent connections without requiring too many hardware resources (expensive computers with lots of CPUs, RAM and fast disks).<ref name="ws-root-bench-2016">{{Cite web|url=https://www.rootusers.com/linux-web-server-performance-benchmark-2016-results/|title=Linux Web Server Performance Benchmark - 2016 results|author=|date=8 March 2016 |publisher=RootUsers|access-date=2021-12-22|archive-date=23 December 2021|archive-url=https://web.archive.org/web/20211223131547/https://www.rootusers.com/linux-web-server-performance-benchmark-2016-results/|url-status=live}}</ref>