When most people think of the web, they do not stop to think about the computers that actually make it work. After all, the Internet itself is just a bunch of servers – computers connected together to form a monstrously large network.
The web is a particular aspect of the Internet that requires web servers to run. A server machine can have many functions, but to be a web server, it needs web server software. Netcraft has been tracking web servers since the early days of the web, and every month it lists the most widely used web servers. The following are the top web server software applications that power the web.
1. Apache HTTP Server
Tried, tested, and geek-approved, Apache web server is one of the oldest and most prolific. Originally based on NCSA HTTPd, Apache now has the largest market share of web servers. It also has many derivatives that may run on an undisclosed number of web servers around the world.
Apache is free and open source, released under the Apache Software Foundation’s “Apache License”. Users are free to download, install, modify, and redistribute it. Because of this, most Linux distributions, BSD variants, and other operating systems either include it or provide binary installation packages for it. Apache is also highly extensible with full support for modules, many of which come with the default installation. Apache also runs on Microsoft Windows. Some of the world’s best web hosting providers host thousands of websites with Apache.
2. Microsoft IIS
Unlike most of the others on the list, Microsoft’s Internet Information Services (IIS) is a commercial and proprietary web server that exclusively comes with certain versions of Microsoft Windows, such as Windows Server 2008. It is second to Apache largely because it does not support versions of Linux, BSD, and Unix - operating systems that power most of the world’s servers.
Like Apache, IIS is highly modular, allowing for additional modules to be plugged into the main web server. A number of default modules come with the system upon installation.
Pronounced “engine X”, Nginx is a lightweight web server that is designed to carry a heavy load. It features additional tools such as a load balancer, making it ideal for sites that need to take on high traffic.
Many of the world’s high-traffic websites prefer Nginx and its reverse proxy server. It is designed to be highly scalable, and can support a multitude of simultaneous connections with getting bogged down. Nginx is free and open source software released under a BSD-style license. It runs on most Unix-like operating systems, including Linux, BSD, Solaris, and Mac OS X. It also runs on Windows.
Many top sites like Facebook and Hulu run Nginx
Unlike the others on the list, GWS is not available to the general public no matter what operating system you run. It is the internal web server developed and run exclusively by Google. Because Google’s network is so large and its website is run from so many servers around the world, its GWS web server accounts for a significant amount of traffic.
Little is known about the internal systems that power Google. Their web servers run Linux, but GWS is not based on Apache, according to Google. What we do know is that it has a significant impact on the web, and Google has undoubtedly taken every step possible to optimize it to be one of the fastest and most efficient high-volume web servers.
The name says it all. Lighttpd is designed to be lightweight. While other web servers may focus on robust feature sets and extensibility, Lighttpd is interested in speed, low-impact operation, and high-volume traffic.
Servers that get a lot of traffic often suffer from what one could call the network equivalent of a traffic jam. Lighttpd can reportedly handle tens of thousands of simultaneous connections without putting a strain on the CPU and memory.
Although it is lightweight and free, it still has a number of important features like FastCGI, load balancing, and HTTP compression. Many BitTorrent sites and other high traffic sites use it. Some sites also use it specifically to push static content, while using other web servers to power their dynamic content. These include YouTube and Wikipedia.
Open Source Web
As you can see from the list, free and open source web servers dominate the web, and many of the world’s major websites use and contribute to open source technology. Examples include Google, Facebook, and Amazon. Still, Microsoft’s web server also plays an important role, and other proprietary web servers like LiteSpeed also have some proponents. But Apache is at the top of the list, and its free and open model for developments fits with the free and collaborative nature of the web.
Tavis J. Hampton is a writer and chief editor of TavisOnline.com, which provides insight into Linux, KDE, free software in general, and open web technology.