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The term Web server can mean one of two things: Image File history File linksMetadata Size of this preview: 800 × 533 pixel Image in higher resolution (3504 × 2336 pixel, file size: 980 KB, MIME type: image/jpeg) This is a picture taken of my web server in 2005. ...
Image File history File linksMetadata Size of this preview: 800 × 533 pixel Image in higher resolution (3504 × 2336 pixel, file size: 980 KB, MIME type: image/jpeg) This is a picture taken of my web server in 2005. ...
Dell Inc. ...
PowerEdge is the name given to all of the servers produced by Dell, Inc. ...
WWWs historical logo designed by Robert Cailliau The World Wide Web is a system of interlinked, hypertext documents accessed via the Internet. ...
This article does not cite any references or sources. ...
- A computer program that is responsible for accepting HTTP requests from clients, which are known as Web browsers, and serving them HTTP responses along with optional data contents, which usually are Web pages such as HTML documents and linked objects (images, etc.).
- A computer that runs a computer program which provides the functionality described in the first sense of the term.
A computer program is a collection of instructions that describe a task, or set of tasks, to be carried out by a computer. ...
HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ...
An example of a web browser (Internet Explorer), displaying the English Wikipedia main page. ...
HTML, short for Hypertext Markup Language, is the predominant markup language for the creation of web pages. ...
The NASA Columbia Supercomputer. ...
Common features Although Web server programs differ in detail, they all share some basic common features. Image File history File links Download high-resolution version (512x768, 111 KB) William Viker <william. ...
Image File history File links Download high-resolution version (512x768, 111 KB) William Viker <william. ...
The My Opera Community is the support community for the Opera web Browser. ...
- HTTP: every Web server program operates by accepting HTTP requests from the network, and providing an HTTP response to the requester. The HTTP response typically consists of an HTML document, but can also be a raw text file, an image, or some other type of document (defined by MIME-types); if something bad is found in client request or while trying to serve the request, a Web server has to send an error response which may include some custom HTML or text messages to better explain the problem to end users.
- Logging: usually Web servers have also the capability of logging some detailed information, about client requests and server responses, to log files; this allows the Webmaster to collect statistics by running log analyzers on log files.
In practice many Web servers implement the following features too. HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ...
HTML, short for Hypertext Markup Language, is the predominant markup language for the creation of web pages. ...
Multipurpose Internet Mail Extensions (MIME) is an Internet Standard that extends the format of e-mail to support: text in character sets other than US-ASCII; non-text attachments; multi-part message bodies; and header information in non-ASCII character sets. ...
Data logging is the practice of recording sequential data, often chronologically. ...
Data logging is the practice of recording sequential data, often chronologically. ...
A server log is a file (or several files) automatically created and maintained by a server of activity performed by it. ...
A webmaster is a person responsible for designing, developing, marketing, or maintaining Web site(s). ...
Web log analysis software (also called a web log analyzer) is software that parses a log file from a web server (like Apache), and based on the values contained in the log file, derives indicators about who, when and how a web server is visited. ...
- Authentication, optional authorization request (request of user name and password) before allowing access to some or all kind of resources.
- Handling of not only static content (file content recorded in server's filesystem(s)) but of dynamic content too by supporting one or more related interfaces (SSI, CGI, SCGI, FastCGI, JSP, PHP, ASP, ASP .NET, Server API such as NSAPI, ISAPI, etc.).
- HTTPS support (by SSL or TLS) to allow secure (encrypted) connections to the server on the standard port 443 instead of usual port 80.
- Content compression (i.e. by gzip encoding) to reduce the size of the responses (to lower bandwidth usage, etc.).
- Virtual Hosting to serve many web sites using one IP address.
- Large file support to be able to serve files whose size is greater than 2 GB on 32 bit OS.
- Bandwidth throttling to limit the speed of responses in order to not saturate the network and to be able to serve more clients.
Authentication (from Greek αυθεντικός; real or genuine, from authentes; author) is the act of establishing or confirming something (or someone) as authentic, that is, that claims made by or about the thing are true. ...
In security engineering and computer security, authorization, is a part of the operating system that protects computer resources by only allowing those resources to be used by resource consumers that have been granted authority to use them. ...
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A password is a form of secret authentication data that is used to control access to a resource. ...
See Filing system for this term as it is used in libraries and offices In computing, a file system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. ...
Dynamic Web pages can be defined as: 1) Web pages containing dynamic content (e. ...
Server Side Includes or SSI is an easy server-side scripting language used almost exclusively for the web. ...
The Common Gateway Interface (CGI) is a standard protocol for interfacing external application software with an information server, commonly a web server. ...
Simple Common Gateway Interface (SCGI) protocol is a replacement for the CGI protocol. ...
FastCGI is a protocol for interfacing interactive programs with a web server. ...
JavaServer Pages (JSP) is a Java technology that allows software developers to dynamically generate HTML, XML or other types of documents in response to a Web client request. ...
PHP is a reflective programming language originally designed for producing dynamic web pages. ...
Active Server Pages (ASP) is Microsofts Server-side script engine for dynamically-generated web pages. ...
ASP.NET is a web application framework marketed by Microsoft. ...
In computer science, the Server Application Programming Interface (SAPI) is the generic term used to designate direct module interfaces to web server applications such as the Apache HTTP Server, Microsoft IIS, or iPlanet. ...
NSAPI - Network (Layer) Service Access Point Identifier. ...
The Internet Service Application Programming Interface (ISAPI) is the API of Internet Information Services (IIS), Microsofts collection of Windows-based network services. ...
https is a URI scheme used to indicate a secure HTTP connection. ...
Secure Sockets Layer (SSL) and Transport Layer Security (TLS), its successor, are cryptographic protocols which provide secure communications on the Internet. ...
Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide secure communications on the Internet for such things as web browsing, e-mail, Internet faxing, instant messaging and other data transfers. ...
TCP and UDP are transport protocols used for communication between computers. ...
In computer science and information theory, data compression or source coding is the process of encoding information using fewer bits (or other information-bearing units) than an unencoded representation would use through use of specific encoding schemes. ...
The correct title of this article is . ...
Virtual hosting is a method that web servers use to host more than one domain name on the same computer and IP address. ...
This article or section does not cite any references or sources. ...
Large file support, often abberviated to LFS, is the term frequently applied to the support for files larger than 2 GB on 32-bit operating systems. ...
It has been suggested that Maintenance OS be merged into this article or section. ...
Bandwidth throttling is a method of ensuring a bandwidth intensive device, such as a server, will limit (throttle) the number of requests it will respond to within a specified period of time. ...
Origin of returned content The origin of the content sent by server is called: - static if it comes from an existing file lying on a filesystem;
- dynamic if it is dynamically generated by some other program or script or API called by the Web server.
Serving static content is usually much faster (from 2 to 100 times) than serving dynamic content, especially if the latter involves data pulled from a database. A computer file is a collection of information that is stored in a computer system and can be identified by its full path name. ...
See Filing system for this term as it is used in libraries and offices In computing, a file system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. ...
Dynamic Web pages can be defined as: 1) Web pages containing dynamic content (e. ...
Scripting programming languages (commonly called scripting languages or script languages) are computer programming languages designed for scripting the operation of a computer. ...
API may refer to: In computing, application programming interface In petroleum industry, American Petroleum Institute In education, Academic Performance Index This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...
This article does not cite any references or sources. ...
Path translation Web servers are able to map the path component of a Uniform Resource Locator (URL) into: // Uniform Resource Locator (URL) is a technical, Web-related term used in two distinct meanings: In popular usage, it is a widespread synonym for Uniform Resource Identifier (URI) — many popular and technical texts will use the term URL when referring to URI; Strictly, the idea of a uniform syntax for...
- a local file system resource (for static requests);
- an internal or external program name (for dynamic requests).
For a static request the URL path specified by the client is relative to the Web server's root directory. It has been suggested that Crash counting be merged into this article or section. ...
Consider the following URL as it would be requested by a client:
http://www.example.com/path/file.html The client's Web browser will translate it into a connection to www.example.com with the following HTTP 1.1 request: GET /path/file.html HTTP/1.1 Host: www.example.com The Web server on www.example.com will append the given path to the path of its root directory. On Unix machines, this is commonly /var/www/htdocs. The result is the local file system resource: Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ...
/var/www/htdocs/path/file.html The Web server will then read the file, if it exists, and send a response to the client's Web browser. The response will describe the content of the file and contain the file itself.
Performances Web servers (programs) are supposed to serve requests quickly from more than one TCP/IP connection at a time.
Main key performance parameters (measured under a varying load of clients and requests per client), are:
- number of requests per second (depending on the type of request, etc.);
- latency time in milliseconds for each new connection or request;
- throughput in bytes per second (depending on file size, cached or not cached content, available network bandwidth, etc.).
Above three parameters vary noticeably depending on the number of active connections, so a fourth parameter is the concurrency level supported by a Web server under a specific configuration.
Last but not least, the specific server model used to implement a Web server program can bias the performance and scalability level that can be reached. It has been suggested that this article or section be merged with Scale (computing). ...
Load limits A web server (program) has defined load limits, because it can handle only a limited number of concurrent client connections (usually between 2 and 60,000, by default between 500 and 1,000) per IP address (and IP port) and it can serve only a certain maximum number of requests per second depending on: This article or section does not cite any references or sources. ...
- its own settings;
- the HTTP request type;
- content origin (static or dynamic);
- the fact that the served content is or is not cached;
- the hardware and software limits of the OS where it is working.
When a web server is near to or over its limits, it becomes overloaded and thus unresponsive. HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ...
Look up cache in Wiktionary, the free dictionary. ...
Computer hardware is the physical part of a computer, including the digital circuitry, as distinguished from the computer software that executes within the hardware. ...
It has been suggested that this article or section be merged with Computer program. ...
It has been suggested that Maintenance OS be merged into this article or section. ...
Overload causes
A daily graph of a web server's load, indicating a spike in the load early in the day. At any time Web servers can be overloaded because of: Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
- too much legitimate Web traffic (i.e. thousands or even millions of clients hitting the Web site in a short interval of time);
- DDoS (Distributed Denial of Service) attacks;
- Computer worms that sometimes cause abnormal traffic because of millions of infected computers (not coordinated among them);
- XSS viruses can cause high traffic because of millions of infected browsers and/or web servers;
- Internet web robots traffic not filtered / limited on large web sites with very few resources (bandwidth, etc.);
- Internet (network) slowdowns, so that client requests are served more slowly and the number of connections increases so much that server limits are reached;
- Web servers (computers) partial unavailability, this can happen because of required / urgent maintenance or upgrade, HW or SW failures, back-end (i.e. DB) failures, etc.; in these cases the remaining web servers get too much traffic and of course they become overloaded.
A denial-of-service attack (also, DoS attack) is an attack on a computer system or network that causes a loss of service to users, typically the loss of network connectivity and services by consuming the bandwidth of the victim network or overloading the computational resources of the victim system. ...
This is about the computer worm. ...
A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. ...
The term web server can mean one of two things: a computer responsible for serving web pages, mostly HTML documents, via the HTTP protocol to clients, mostly web browsers; a software program that is working as a daemon serving web documents. ...
Internet bots, also known as web robots, WWW robots or simply bots, are software applications that run automated tasks over the internet. ...
The NASA Columbia Supercomputer. ...
Computer hardware is the physical part of a computer, including the digital circuitry, as distinguished from the computer software that executes within the hardware. ...
It has been suggested that this article or section be merged with Computer program. ...
In their most general meanings, the terms front end and back end refer to the initial and the end stages of a process flow. ...
This article does not cite any references or sources. ...
Overload symptoms The symptoms of an overloaded Web server are: - requests are served with (possibly long) delays (from 1 second to a few hundred seconds);
- 500, 502, 503, 504 HTTP errors are returned to clients (sometimes also unrelated 404 error or even 408 error may be returned);
- TCP connections are refused or reset (interrupted) before any content is sent to clients;
- in very rare cases, only partial contents are sent (but this behaviour may well be considered a bug, even if it usually depends on unavailable system resources).
The following is a list of HTTP response status codes and standard associated phrases, intended to give a short textual description of the status. ...
Mozilla Firefox displaying an Apache HTTP Server 404 error page. ...
The following is a list of HTTP response status codes and standard associated phrases, intended to give a short textual description of the status. ...
The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite, often simply referred to as TCP/IP. Using TCP, applications on networked hosts can create connections to one another, over which they can exchange streams of data using Stream Sockets. ...
A software bug is an error, flaw, mistake, failure, or fault in a computer program that prevents it from behaving as intended (e. ...
Anti-overload techniques To partially overcome above load limits and to prevent the overload scenario, most popular Web sites use common techniques like: A scenario (from the Italian, that which is pinned to the scenery) is a brief description of an event or a series of events. ...
- managing network traffic, by using:
- Firewalls to block unwanted traffic coming from bad IP sources or having bad patterns;
- HTTP traffic managers to drop, redirect or rewrite requests having bad HTTP patterns;
- Bandwidth management and Traffic shaping, in order to smooth down peaks in network usage;
- deploying Web cache techniques;
- using different domain names to serve different (static and dynamic) content by separate Web servers, i.e.:
- using different domain names and / or computers to separate big files from small and medium sized files; the idea is to be able to fully cache small and medium sized files and to efficiently serve big or huge (over 10 - 1000 MB) files by using different settings;
- using many Web servers (programs) per computer, each one bound to its own network card and IP address;
- using many Web servers (computers) that are grouped together so that they act or are seen as one big Web server, see also: Load balancer;
- adding more HW resources (i.e. RAM, disks) to each computer;
- tuning OS parameters for HW capabilities and usage;
- using more efficient computer programs for Web servers, etc.;
- using other workarounds, specially if dynamic content is involved.
Firewall separating zones of trust A firewall is a hardware or software device which is configured to permit, deny or proxy data through a computer network which has different levels of trust. ...
HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ...
The tone or style of this article or section may not be appropriate for Wikipedia. ...
This article needs additional references or sources for verification. ...
Web caching is the caching of web documents (e. ...
The term domain name has multiple related meanings: A name that identifies a computer or computers on the internet. ...
The term domain name has multiple related meanings: A name that identifies a computer or computers on the internet. ...
The NASA Columbia Supercomputer. ...
Look up cache in Wiktionary, the free dictionary. ...
The NASA Columbia Supercomputer. ...
A network card, network adapter or NIC (network interface controller) is a piece of computer hardware designed to allow computers to communicate over a computer network. ...
This article or section does not cite any references or sources. ...
It has been suggested that this article or section be merged into Load balancing (computing). ...
For other uses, see Hardware (disambiguation). ...
Look up RAM, Ram, ram in Wiktionary, the free dictionary. ...
Disk storage is a group of data storage mechanisms for computers; data are transferred to planar surfaces or disks for temporary or permanent storage. ...
The NASA Columbia Supercomputer. ...
It has been suggested that Maintenance OS be merged into this article or section. ...
For other uses, see Hardware (disambiguation). ...
A computer program is a collection of instructions that describe a task, or set of tasks, to be carried out by a computer. ...
A workaround is a bypass of a recognized problem in a system. ...
Historical notes
 The world's first web server. In 1989 Tim Berners-Lee proposed to his employer CERN (European Organization for Nuclear Research) a new project, which had the goal of easing the exchange of information between scientists by using a hypertext system. As a result of the implementation of this project, in 1990 Berners-Lee wrote two programs: Image File history File links Download high resolution version (1000x750, 274 KB)This NeXT workstation (a NeXTcube) was used by Tim Berners-Lee as the first Web server on the World Wide Web. ...
Image File history File links Download high resolution version (1000x750, 274 KB)This NeXT workstation (a NeXTcube) was used by Tim Berners-Lee as the first Web server on the World Wide Web. ...
Year 1989 (MCMLXXXIX) was a common year starting on Sunday (link displays 1989 Gregorian calendar). ...
Sir Tim Berners-Lee Sir Tim (Timothy John) Berners-Lee, KBE (TimBL or TBL) (b. ...
CERN logo The European Organization for Nuclear Research (French: ), commonly known as CERN (see Naming), pronounced (or in French), is the worlds largest particle physics laboratory, situated just northwest of Geneva on the border between France and Switzerland. ...
- a browser called WorldWideWeb;
- the world's first Web server, which ran on NeXTSTEP; NOTE: today, this machine is on exhibition at CERN's public museum, Microcosm.
The first web server in U.S.A. was installed on December 12, 1991 at SLAC [1] An example of a web browser (Internet Explorer), displaying the English Wikipedia main page. ...
WorldWideWeb was the worlds first web browser and WYSIWYG (What you see is what you get) HTML editor. ...
NEXTSTEP is the original object-oriented, multitasking operating system that NeXT Computer, Inc. ...
CERN logo The European Organization for Nuclear Research (French: ), commonly known as CERN (see Naming), pronounced (or in French), is the worlds largest particle physics laboratory, situated just northwest of Geneva on the border between France and Switzerland. ...
Motto: (traditional) In God We Trust (official, 1956–present) Anthem: The Star-Spangled Banner Capital Washington, D.C. Largest city New York City Official language(s) None at the federal level; English de facto Government Federal Republic - President George W. Bush (R) - Vice President Dick Cheney (R) Independence - Declared - Recognized...
The Stanford Linear Accelerator Center (SLAC) is a U.S. national laboratory operated by Stanford University for the U.S. Department of Energy. ...
Between 1991 and 1994 the simplicity and effectiveness of early technologies used to surf and exchange data through the WorldWideWeb helped a lot to: WorldWideWeb was the worlds first web browser and WYSIWYG (What you see is what you get) HTML editor. ...
- port them to many different OSs;
- spread their use among lots of different social groups of people, first in scientific organizations, then in universities and finally in industry.
In 1994 Tim Berners-Lee decided to constitute the World Wide Web Consortium to regulate the further development of the many technologies involved (HTTP, HTML, etc.) through a standardization process. It has been suggested that Maintenance OS be merged into this article or section. ...
Sir Tim Berners-Lee Sir Tim (Timothy John) Berners-Lee, KBE (TimBL or TBL) (b. ...
It has been suggested that W3C Markup Validation Service be merged into this article or section. ...
HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ...
HTML, short for Hypertext Markup Language, is the predominant markup language for the creation of web pages. ...
The following years are recent history which has seen an exponential growth (become explosive after 2000) of the number of web sites and, of course, of the number of Web Servers. A website, Web site or WWW site (often shortened to just site) is a collection of webpages, that is, HTML/XHTML documents accessible via HTTP on the Internet; all publicly accessible websites in existence comprise the World Wide Web. ...
Software As of July 2007, the most common HTTP serving programs are:[2] † Microsoft is the sum of sites running Microsoft-Internet-Information-Server, Microsoft-IIS, Microsoft-IIS-W, Microsoft-PWS-95, & Microsoft-PWS.
‡ Sun is the sum of sites running SunONE, iPlanet-Enterprise, Netscape-Enterprise, Netscape-FastTrack, Netscape-Commerce, Netscape-Communications, Netsite-Commerce & Netsite-Communications. The Apache HTTP Server, commonly referred to simply as Apache, is a web server notable for playing a key role in the initial growth of the World Wide Web. ...
Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ...
The Sun (Latin: Sol) is the star at the center of the Solar System. ...
It has been suggested that Lighty Tray be merged into this article or section. ...
There are thousands of different Web server programs available, many of which are specialized for very specific purposes, so the fact that a web server is not very popular does not necessarily mean that it has a lot of bugs or poor performance.
See Category:Web server software for a longer list of HTTP server programs.
Statistics The most popular Web servers, used for public Web sites, are tracked by Netcraft Web Server Survey, with details given by Netcraft Web Server Reports.
According to this site, Apache has been the most popular Web server on the Internet since April of 1996. The January 2007 Netcraft Web Server Survey found that about 60% of the Web sites on the Internet were using Apache, followed by IIS with about 30% share.
Another site providing statistics is SecuritySpace ([3]), which also provides a detailed breakdown for each version of Web server: [4]
See also - HTTP, HTTPS
- Comparison of web servers
- Tiny web servers
- SSI, CGI, SCGI, FastCGI, PHP, Java Servlet, JavaServer Pages, ASP, ASP .NET, Server API
- Virtual hosting
- LAMP (software bundle)
- Web browser
- Web log analysis software
- Web hosting service
- Application server
- Mac OS X Server
- HTTP compression
HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ...
https is a URI scheme used to indicate a secure HTTP connection. ...
This article is a comparison of Web servers. ...
This article does not cite any references or sources. ...
Server Side Includes or SSI is an easy server-side scripting language used almost exclusively for the web. ...
The Common Gateway Interface (CGI) is a standard protocol for interfacing external application software with an information server, commonly a web server. ...
Simple Common Gateway Interface (SCGI) protocol is a replacement for the CGI protocol. ...
FastCGI is a protocol for interfacing interactive programs with a web server. ...
PHP is a reflective programming language originally designed for producing dynamic web pages. ...
The Java Servlet API allows a software developer to add dynamic content to a Web server using the Java platform. ...
JavaServer Pages (JSP) is a Java technology that allows software developers to dynamically generate HTML, XML or other types of documents in response to a Web client request. ...
Active Server Pages (ASP) is Microsofts Server-side script engine for dynamically-generated web pages. ...
ASP.NET is a web application framework marketed by Microsoft. ...
In computer science, the Server Application Programming Interface (SAPI) is the generic term used to designate direct module interfaces to web server applications such as the Apache HTTP Server, Microsoft IIS, or iPlanet. ...
It has been suggested that this article or section be merged into shared web hosting service. ...
The acronym LAMP refers to a solution stack of software programs, commonly open-source programs, used together to run dynamic Web sites or servers. ...
An example of a web browser (Internet Explorer), displaying the English Wikipedia main page. ...
Web log analysis software (also called a web log analyzer) is software that parses a log file from a web server (like Apache), and based on the values contained in the log file, derives indicators about who, when and how a web server is visited. ...
An example of rack mounted servers. ...
An application server is a software engine that delivers applications to client computers or devices. ...
Mac OS X Server is the server-oriented version of Apples desktop operating system, Mac OS X. Mac OS X, in both desktop and server versions, is a Unix-like operating system based on technology that Apple acquired from NeXT Computer. ...
HTTP compression is a capability built into both web servers and web browsers, to make better use of available bandwidth. ...
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