The Apache HTTP Server ( / ə ˈ p æ tʃ i / ə- PATCH -ee ) is a free and open-source cross-platform web server software, released under the terms of Apache License 2.0 . It is developed and maintained by a community of developers under the auspices of the Apache Software Foundation .
62-531: The vast majority of Apache HTTP Server instances run on a Linux distribution , but current versions also run on Microsoft Windows , OpenVMS , and a wide variety of Unix-like systems. Past versions also ran on NetWare , OS/2 and other operating systems, including ports to mainframes. Originally based on the NCSA HTTPd server, development of Apache began in early 1995 after work on the NCSA code stalled. Apache played
124-448: A desktop environment (most commonly GNOME , KDE Plasma , or Xfce ), a sound server (usually either PulseAudio or more recently PipeWire ), and other related programs may be included or installed by the user. Typically, most of the included software is free and open-source software – made available both as binary for convenience and as source code to allow for modifying it. A distro may also include proprietary software that
186-500: A package manager , an init system (such as systemd , OpenRC , or runit ), GNU tools and libraries , documentation, IP network configuration utilities, the getty TTY setup program, and many more. To provide a desktop experience (most commonly the Mesa userspace graphics drivers) a display server (the most common being the X.org Server , or, more recently, a Wayland compositor such as Sway , KDE 's KWin , or GNOME 's Mutter ),
248-439: A CD with only a small amount of data on it. New users tend to begin by partitioning a hard drive in order to keep their previously installed operating system. The Linux distribution can then be installed on its own separate partition without affecting previously saved data. In a Live CD setup, the computer boots the entire operating system from CD without first installing it on the computer's hard disk. Many distributions have
310-520: A Live CD installer , where the computer boots the operating system from the disk, and it can then be installed on the computer's hard disk, providing a seamless transition from the OS running from the CD to the OS running from the hard disk. Both servers and personal computers that come with Linux already installed are available from vendors including Hewlett-Packard , Dell and System76 . On embedded devices, Linux
372-577: A bunch of software patches, right? So it's a patchy Web server." I went, "Oh, all right." ... When I thought of the name, no. It just sort of connoted: "Take no prisoners. Be kind of aggressive and kick some ass." In January 2023, the US-based non-profit Natives in Tech accused the Apache Software Foundation of cultural appropriation and urged them to change the foundation's name, and consequently also
434-631: A conscious effort to use a different operating system, and they must either perform the actual installation themselves, or depend on support from a friend, relative, or computer professional. Mod ssl mod_ssl is an optional module for the Apache HTTP Server . It provides strong cryptography for the Apache v1.3 and v2 webserver via the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) cryptographic protocols by
496-512: A distribution, an administrator may create a "distributionless" installation. It is possible to build such systems from scratch, avoiding distributions altogether. One needs a way to generate the first binaries until the system is self-hosting . This can be done via compilation on another system capable of building binaries for the intended target (possibly by cross-compilation ). For example, see Linux From Scratch . In broad terms, Linux distributions may be: The diversity of Linux distributions
558-493: A key role in the initial growth of the World Wide Web , quickly overtaking NCSA HTTPd as the dominant HTTP server. In 2009, it became the first web server software to serve more than 100 million websites . As of March 2022, Netcraft estimated that Apache served 23.04% of the million busiest websites, while Nginx served 22.01%; Cloudflare at 19.53% and Microsoft Internet Information Services at 5.78% rounded out
620-637: A new SLS-based distribution, Slackware , was released by Patrick Volkerding . Also dissatisfied with SLS, Ian Murdock set to create a free distribution by founding Debian in August 1993, with first public BETA released in January 1994 and first stable version in June 1996. Users were attracted to Linux distributions as alternatives to the DOS and Microsoft Windows operating systems on IBM PC compatible computers, Mac OS on
682-464: A package are present (and either notify the user to install them, or install them automatically). The package can also be provided as source code to be compiled on the system. Most distributions install packages, including the kernel and other core operating system components, in a predetermined configuration. A few now require or permit configuration adjustments at first install time. This makes installation less daunting, particularly for new users, but
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#1732845080629744-404: A proprietary operating system or by translating proprietary API calls (e.g., calls to Microsoft's Win32 or DirectX APIs) into native Linux API calls. A virtual machine can also be used to run a proprietary OS (like Microsoft Windows) on top of Linux. Computer hardware is usually sold with an operating system other than Linux already installed by the original equipment manufacturer (OEM). In
806-607: A robust, commercial-grade, feature-rich and freely available source code implementation of an HTTP (Web) server. The project is jointly managed by a group of volunteers located around the world, using the Internet and the Web to communicate, plan, and develop the server and its related documentation. This project is part of the Apache Software Foundation . In addition, hundreds of users have contributed ideas, code, and documentation to
868-430: A series of patches ". There are other sources for the "patchy" software pun theory, including the project's official documentation in 1995, which stated: "Apache is a cute name which stuck. It was based on some existing code and a series of software patches, a pun on 'A PAtCHy' server." But in an April 2000 interview, Behlendorf asserted that the origins of Apache were not a pun, stating: The name literally came out of
930-509: A specific instruction set , while some (such as Gentoo ) are distributed mostly in source code form and must be built before installation. Linus Torvalds developed the Linux kernel and distributed its first version, 0.01, in 1991. Linux was initially distributed as source code only, and later as a pair of downloadable floppy disk images: one bootable and containing the Linux kernel itself, and
992-713: A specific application or service. Examples of packages are a library for handling the PNG image format, a collection of fonts, and a web browser . The package is typically provided as compiled code, with installation and removal of packages handled by a package management system (PMS) rather than a simple file archiver . Each package intended for such a PMS contains meta-information such as its description, version number, and its dependencies (other packages it requires to run). The package management system evaluates this meta-information to allow package searches, perform automatic upgrades to newer versions, and to check that all dependencies of
1054-416: Is a Linux distribution that can be booted from removable storage media such as optical discs or USB flash drives , instead of being installed on and booted from a hard disk drive . The portability of installation-free distributions makes them advantageous for applications such as demonstrations, borrowing someone else's computer, rescue operations, or as installation media for a standard distribution. When
1116-757: Is a Linux distribution; others, such as Google engineer Patrick Brady, disagree by noting the lack of support for many GNU tools in Android, including glibc . Other Linux-kernel-based operating systems include Tizen , Mer / Sailfish OS , KaiOS and Amazon's Kindle firmware . Lightweight Linux distributions are those that have been designed with support for older hardware in mind, allowing older hardware to still be used productively, or, for maximum possible speed in newer hardware by leaving more resources available for use by applications. Examples include Tiny Core Linux , Puppy Linux and Slitaz . Other distributions target specific niches, such as: The Free Standards Group
1178-496: Is about 3.67%. Many Linux distributions provide an installation system akin to that provided with other modern operating systems. Other distributions, including Gentoo Linux , provide only the binaries of a basic kernel, compilation tools, and an installer; the installer compiles all the requested software for the specific architecture of the user's computer, using these tools and the software's source code. Distributions are normally segmented into packages . Each package contains
1240-531: Is an organization formed by major software and hardware vendors that aims to improve interoperability between different distributions. Among their proposed standards are the Linux Standard Base , which defines a common ABI and packaging system for Linux, and the Filesystem Hierarchy Standard which recommends a standard filenaming chart, notably the basic directory names found on the root of
1302-671: Is due to technical, organizational, and philosophical variation among vendors and users. The permissive licensing of free software means that users with sufficient knowledge and interest can customize any existing distribution, or design one to suit their own needs. Rolling Linux distributions are kept current using small and frequent updates . The terms partially rolling and partly rolling (along with synonyms semi-rolling and half-rolling ), fully rolling , truly rolling and optionally rolling are sometimes used by software developers and users. Repositories of rolling distributions usually contain very recent software releases —often
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#17328450806291364-489: Is not always acceptable. For specific requirements, much software must be carefully configured to be useful, to work correctly with other software, or to be secure, and local administrators are often obliged to spend time reviewing and reconfiguring it. Some (but not all) distributions go to considerable lengths to adjust and customize the software they include, and some provide configuration tools to help users do so. By obtaining and installing everything normally provided in
1426-545: Is not available in source code form, such as a device driver binary . A distro may be described as a particular assortment of application and utility software (various GNU tools and libraries, for example), packaged with the Linux kernel in such a way that its capabilities meet users' needs. The software is usually adapted to the distribution and then combined into software packages by the distribution's maintainers. The software packages are available online in repositories , which are storage locations usually distributed around
1488-424: Is often referred to as "distro hopping". Virtual machine software such as VirtualBox and VMware Workstation virtualize hardware allowing users to test live media on a virtual machine without installing to the real system. Some websites like DistroWatch offer lists of distributions, and link to screenshots of operating systems as a way to get a first impression of various distributions. Some distributions let
1550-513: Is sometimes possible on closely related distributions. There are several ways to install a Linux distribution. The most common method of installing Linux is by booting from a live USB memory stick , which can be created by using a USB image writer application and the ISO image, which can be downloaded from various Linux distribution websites. DVD disks, CD disks, network installations and even other hard drives can also be used as "installation media". In
1612-563: Is still half as fast as nginx, e.g. The Apache HTTP Server codebase was relicensed to the Apache 2.0 License (from the previous 1.1 license) in January 2004, and Apache HTTP Server 1.3.31 and 2.0.49 were the first releases using the new license. The OpenBSD project did not like the change and continued the use of pre-2.0 Apache versions, effectively forking Apache 1.3.x for its purposes. They initially replaced it with Nginx , and soon after made their own replacement, OpenBSD Httpd, based on
1674-462: Is typically held in the device's firmware and may or may not be consumer-accessible. Anaconda , one of the more popular installers, is used by Red Hat Enterprise Linux , Fedora (which uses the Fedora Media Writer ) and other distributions to simplify the installation process. Debian, Ubuntu and many others use Debian-Installer . The process of constantly switching between distributions
1736-438: Is under a BSD-style license . The version for v2.0 and later, in contrast, is maintained by Apache Software Foundation and licensed under Apache License 2.0. It is possible to provide HTTP and HTTPS with a single server machine, because HTTP and HTTPS use different server ports, so there is no direct conflict between them. It is either the maintainer who would run two separate Apache server instances (one binds to port 80,
1798-529: The Apple Macintosh , and proprietary versions of Unix . Most early adopters were familiar with Unix from work or school. They embraced Linux distributions for their low (or absent) cost, and the availability of the source code for most or all of their software. As of 2024, Linux has become more popular in server and embedded devices markets than in the desktop market. It is used in approximately 58.9% of web servers; its current operating system market share
1860-425: The software development process , standard releases require significant development effort to keep old versions up-to-date by propagating bug fixes back to the newest branch, versus focusing on the newest development branch . Also, unlike rolling releases, standard releases require more than one code branch to be developed and maintained, which increases the workload of the software developers and maintainers. On
1922-400: The 1990s, Linux distributions were installed using sets of floppy disks but this has been abandoned by all major distributions. By the 2000s many distributions offered CD and DVD sets with the vital packages on the first disc and less important packages on later ones. Some distributions, such as Debian also enabled installation over a network after booting from either a set of floppy disks or
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1984-459: The Apache developers created the Event MPM, which mixes the use of several processes and several threads per process in an asynchronous event-based loop . This architecture as implemented in the Apache 2.4 series performs at least as well as event-based web servers, according to Jim Jagielski and other independent sources. However, some independent but significantly outdated benchmarks show that it
2046-560: The Relayd project. Version 1.1: The Apache License 1.1 was approved by the ASF in 2000: The primary change from the 1.0 license is in the 'advertising clause' (section 3 of the 1.0 license); derived products are no longer required to include attribution in their advertising materials, only in their documentation. Version 2.0: The ASF adopted the Apache License 2.0 in January 2004. The stated goals of
2108-406: The blue. I wish I could say that it was something fantastic, but it was out of the blue. I put it on a page and then a few months later when this project started, I pointed people to this page and said: "Hey, what do you think of that idea?" ... Someone said they liked the name and that it was a really good pun. And I was like, "A pun? What do you mean?" He said, "Well, we're building a server out of
2170-590: The case of IBM PC compatibles , the OS is usually Microsoft Windows ; in the case of Apple 's Mac computers, it has always been macOS ; Sun Microsystems sold SPARC hardware with the Solaris installed; video game consoles such as the Xbox , PlayStation , Wii , and the Nintendo Switch each have their own proprietary OS. This limits Linux's market share: consumers are unaware that an alternative exists, they must make
2232-401: The computer is still connected and not experiencing network problems. The Apache developers have addressed Slowloris with several modules to limit the damage caused; the Apache modules mod_limitipconn, mod_qos , mod_evasive, mod security , mod_noloris, and mod_antiloris have all been suggested as means of reducing the likelihood of a successful Slowloris attack. Since Apache 2.2.15, Apache ships
2294-485: The demands of each particular infrastructure. Choice of MPM and configuration is therefore important. Where compromises in performance must be made, Apache is designed to reduce latency and increase throughput relative to simply handling more requests, thus ensuring consistent and reliable processing of requests within reasonable time-frames. For delivering static pages, Apache 2.2 series was considered significantly slower than nginx and varnish . To address this issue,
2356-613: The help of the Open Source SSL/TLS toolkit OpenSSL . The mod_ssl v1 package was initially created in April 1998 by Ralf S. Engelschall via porting Ben Laurie's Apache-SSL 1.17 source patches for Apache 1.2.6 to Apache 1.3b6. Because of conflicts with Ben Laurie's development cycle it then was re-assembled from scratch for Apache 1.3.0 by merging the old mod_ssl 1.x with the newer Apache-SSL 1.18. From this point on mod_ssl lived its own life as mod_ssl v2. The first publicly released version
2418-459: The latest stable versions available. They have pseudo-releases and installation media that are simply snapshots of the distribution at the time of the installation image's release. Typically, a rolling-release OS installed from older installation medium can be fully updated after it is installed. Depending on the usage case, there can be pros and cons to both standard release and rolling release software development methodologies . In terms of
2480-448: The license included making the license easier for non-ASF projects to use, improving compatibility with GPL-based software, allowing the license to be included by reference instead of listed in every file, clarifying the license on contributions, and requiring a patent license on contributions that necessarily infringe a contributor's own patents. The Apache HTTP Server Project is a collaborative software development effort aimed at creating
2542-420: The module mod_reqtimeout as the official solution supported by the developers. Linux distribution A Linux distribution (often abbreviated as distro ) is an operating system that includes the Linux kernel for its kernel functionality. Although the name does not imply product distribution per se, a distro, if distributed on its own, is often obtained via a website intended specifically for
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2604-502: The names of the software projects it hosts. When Apache is running under Unix , its process name is httpd , which is short for "HTTP daemon ". Apache supports a variety of features, many implemented as compiled modules which extend the core functionality. These can range from authentication schemes to supporting server-side programming languages such as Perl , Python , Tcl and PHP . Popular authentication modules include mod_access, mod_auth, mod_digest, and mod_auth_digest,
2666-435: The need to change the contents of the system's hard disk drive. The website DistroWatch lists many Linux distributions and displays some of the ones that have the most web traffic on the site. The Wikimedia Foundation released an analysis of the browser User Agents of visitors to WMF websites until 2015, which includes details of the most popular Operating System identifiers, including some Linux distributions. Many of
2728-797: The operating system is booted from a read-only medium such as a CD or DVD, any user data that needs to be retained between sessions cannot be stored on the boot device but must be written to another storage device, such as a USB flash drive or a hard disk drive. Many Linux distributions provide a "live" form in addition to their conventional form, which is a network-based or removable-media image intended to be used only for installation; such distributions include SUSE , Ubuntu, Linux Mint , MEPIS and Fedora Linux . Some distributions, including Knoppix , Puppy Linux , Devil-Linux, SuperGamer , SliTaz GNU/Linux and dyne:bolic , are designed primarily for live use. Additionally, some minimal distributions can be run directly from as little space as one floppy disk without
2790-450: The other hand, software features and technology planning are easier in standard releases due to a better understanding of upcoming features in the next version(s). Software release cycles can also be synchronized with those of major upstream software projects, such as desktop environments . As for the user experience , standard releases are often viewed as more stable and bug-free since software conflicts can be more easily addressed and
2852-411: The other to port 443) or use Apache's virtual hosting facility where the maintainer can create two virtual servers which Apache dispatches: one responding to port 80 and speaking HTTP and one responding to port 443 speaking HTTPS. The original mod_ssl in Apache 1.3 available at www.modssl.org is a third-party add-on package requiring additional steps in the compilation and configuration process. Also,
2914-446: The other with a set of GNU utilities and tools for setting up a file system. Since the installation procedure was complicated, especially in the face of growing amounts of available software, distributions sprang up to simplify it. Early distributions included: The two oldest, still active distribution projects started in 1993. The SLS distribution was not well maintained, so in July 1993
2976-467: The popular distributions are listed below. Several operating systems include the Linux kernel, but have a userland that differs significantly from that of mainstream Linux distributions: Whether such operating systems count as a "Linux distribution" is a controversial topic. They use the Linux kernel, so the Linux Foundation and Chris DiBona , Google's former open-source chief, agree that Android
3038-399: The project. Apache 2.4 dropped support for BeOS , TPF , A/UX , NeXT , and Tandem platforms. Apache, like other server software, can be hacked and exploited. The main Apache attack tool is Slowloris , which exploits a bug in Apache software. It creates many sockets and keeps each of them alive and busy by sending several bytes (known as "keep-alive headers") to let the server know that
3100-405: The purpose. Distros have been designed for a wide variety of systems ranging from personal computers (for example, Linux Mint ) to servers (for example, Red Hat Enterprise Linux ) and from embedded devices (for example, OpenWrt ) to supercomputers (for example, Rocks Cluster Distribution ). A distro typically includes many components in addition to the Linux kernel. Commonly, it includes
3162-448: The rolling release model can have advantages in timely security updates, fixing system or application security bugs and vulnerabilities , that standard releases may have to wait till the next release for or patch in various versions. In a rolling release distribution, where the user has chosen to run it as a highly dynamic system, the constant flux of software packages can introduce new unintended vulnerabilities. A "live" distribution
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#17328450806293224-753: The size (weight) of web pages served over HTTP . ModSecurity is an open source intrusion detection and prevention engine for Web applications. Apache logs can be analyzed through a Web browser using free scripts, such as AWStats / W3Perl or Visitors. Virtual hosting allows one Apache installation to serve many different websites . For example, one computer with one Apache installation could simultaneously serve example.com , example.org , test47.test-server.example.edu , etc. Apache features configurable error messages, DBMS -based authentication databases, content negotiation and supports several graphical user interfaces (GUIs). It supports password authentication and digital certificate authentication. Because
3286-507: The software stack more thoroughly tested and evaluated, during the software development cycle. For this reason, they tend to be the preferred choice in enterprise environments and mission-critical tasks. However, rolling releases offer more current software which can also provide increased stability and fewer software bugs along with the additional benefits of new features, greater functionality, faster running speeds, and improved system and application security . Regarding software security ,
3348-447: The source code is freely available, anyone can adapt the server for specific needs, and there is a large public library of Apache add-ons. A more detailed list of features is provided below: Instead of implementing a single architecture, Apache provides a variety of MultiProcessing Modules (MPMs), which allow it to run in either a process -based mode, a hybrid (process and thread ) mode, or an event-hybrid mode, in order to better match
3410-428: The successor to mod_digest. A sample of other features include Secure Sockets Layer and Transport Layer Security support ( mod_ssl ), a proxy module ( mod_proxy ), a URL rewriting module (mod_rewrite), custom log files (mod_log_config), and filtering support (mod_include and mod_ext_filter). Popular compression methods on Apache include the external extension module, mod_gzip, implemented to help with reduction of
3472-495: The top four. For some of Netcraft's other stats, Nginx is ahead of Apache. According to W3Techs' review of all web sites, in June 2022 Apache was ranked second at 31.4% and Nginx first at 33.6%, with Cloudflare Server third at 21.6%. According to The Apache Software Foundation , its name was chosen "from respect for the various Native American nations collectively referred to as Apache , well-known for their superior skills in warfare strategy and their inexhaustible endurance". This
3534-435: The tree of any Linux filesystem. Those standards, however, see limited use, even among the distributions developed by members of the organization. The diversity of Linux distributions means that not all software runs on all distributions, depending on what libraries and other system attributes are required. Packaged software and software repositories are usually specific to a particular distribution, though cross-installation
3596-462: The user install Linux on top of their current system, such as WinLinux or coLinux . Linux is installed to the Windows hard disk partition, and can be started from inside Windows itself. Virtual machines (such as VirtualBox or VMware ) also make it possible for Linux to be run inside another OS. The VM software simulates a separate computer onto which the Linux system is installed. After installation,
3658-640: The virtual machine can be booted as if it were an independent computer. Various tools are also available to perform full dual-boot installations from existing platforms without a CD, most notably: Some specific proprietary software products are not available in any form for Linux. As of September 2015, the Steam gaming service has over 1,500 games available on Linux, compared to 2,323 games for Mac and 6,500 Windows games. Emulation and API-translation projects like Wine and CrossOver make it possible to run non-Linux-based software on Linux systems, either by emulating
3720-724: The world. Beside "glue" components, such as the distribution installers (for example, Debian-Installer and Anaconda ) and the package management systems, very few packages are actually written by a distribution's maintainers. Distributions have been designed for a wide range of computing environments, including desktops , servers , laptops , netbooks , mobile devices (phones and tablets), and embedded systems . There are commercially backed distributions, such as Fedora Linux ( Red Hat ), openSUSE ( SUSE ) and Ubuntu ( Canonical Ltd. ), and entirely community-driven distributions, such as Debian , Slackware , Gentoo and Arch Linux . Most distributions come ready-to-use and prebuilt for
3782-456: Was in a context in which it seemed that the open internet—based on free exchange of open source code—appeared to be soon subjected to a kind of conquer by proprietary software vendor Microsoft ; Apache co-creator Brian Behlendorf —originator of the name—saw his effort somewhat parallel that of Geronimo , Chief of the last of the free Apache peoples. But it conceded that the name "also makes a cute pun on 'a patchy web server '—a server made from
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#17328450806293844-591: Was mod_ssl 2.0.0 from August 10, 1998. After US export restrictions on cryptographic software were loosened, mod_ssl became part of the Apache HTTP Server with the release of Apache httpd 2. As of October 10, 2009, the latest version released for mod_ssl in Apache 1.3 is mod_ssl v2.8.31-1.3.41 on February 8, 2008. The original version created for Apache v1.3 was initially created in April 1998 by Ralf S. Engelschall via porting Ben Laurie's Apache-SSL 1.17 source patches for Apache 1.2.6 to Apache 1.3b6. This version
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