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530eba85dbd41b8a0fa5255d3648d1440199a661slive <p>This glossary defines some of the common terminology related to Apache in
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive particular, and web serving in general. More information on each concept
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna is provided in the links.</p>
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dt><a name="accesscontrol" id="accesscontrol">Access Control</a></dt>
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dd>The restriction of access to network realms. In an Apache context
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna usually the restriction of access to certain <em>URLs</em>.<br /> See: <a
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna href="howto/auth.html">Authentication, Authorization, and Access
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna Control</a>
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dt><a name="algorithm" id="algorithm">Algorithm</a></dt>
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dd>An unambiguous formula or set of rules for solving a problem in a finite
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna number of steps. Algorithms for encryption are usually called
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dt><a name="apacheextensiontool" id="apacheextensiontool">APache
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna eXtension Tool</a> <a name="apxs" id="apxs">(apxs)</a></dt>
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna ref="module">module</glossary> sources into Dynamic Shared Objects
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna (<glossary ref="dso">DSO</glossary>s) and helps install them in the
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna Apache Web server.<br />
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna id="apacheportableruntime">Apache Portable Runtime</a> <a
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dd>A set of libraries providing many of the basic interfaces
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna between the server and the operating system. APR is developed
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna parallel to the Apache HTTP Server as an independent project.<br />
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna See: <a href="http://apr.apache.org/">Apache Portable Runtime
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna Project</a>
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dt><a name="authentication" id="authentication">Authentication</a></dt>
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dd>The positive identification of a network entity such as a server, a
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna client, or a user.<br />
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna See: <a href="howto/auth.html">Authentication, Authorization, and Access
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna Control</a>
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dt><a name="certificate" id="certificate">Certificate</a></dt>
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna <dd>A data record used for authenticating network entities such
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna as a server or a client. A certificate contains X.509 information pieces
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna about its owner (called the subject) and the signing <glossary
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna ref="certificationauthority">Certification Authority</glossary> (called
7e8f5c6496b3825b6b128e2aacc4b1b09d28553dpquerna the issuer), plus the owner's <glossary ref="publickey">public
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive key</glossary> and the
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive signature made by the CA. Network entities verify these signatures
313bb560bc5c323cfd40c9cad7335b4b8e060aedkess using CA certificates.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive id="certificatsigningrequest">Certificate Signing Request</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>An unsigned <glossary ref="certificate">certificate</glossary> for
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive submission to a <glossary ref="certificationauthority">Certification
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive Authority</glossary>, which signs it with the <glossary
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <em>Certificate</em>. Once the CSR is signed, it becomes a real
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive certificate.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive id="certificationauthority">Certification Authority</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>A trusted third party whose purpose is to sign certificates for network
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive entities it has authenticated using secure means. Other network entities
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive can check the signature to verify that a CA has authenticated the bearer
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive of a certificate.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>An algorithm or system for data encryption. Examples are DES, IDEA, RC4,
fb77c505254b6e9c925e23e734463e87574f8f40kess etc.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="ciphertext" id="ciphertext">Ciphertext</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>The result after <glossary ref="plaintext">Plaintext</glossary> is
fb77c505254b6e9c925e23e734463e87574f8f40kess passed through a <glossary ref="cipher">Cipher</glossary>.<br /> See: <a
fb77c505254b6e9c925e23e734463e87574f8f40kess <dt><a name="commongatewayinterface" id="commongatewayinterface">Common
fb77c505254b6e9c925e23e734463e87574f8f40kess Gateway Interface</a> <a name="cgi" id="cgi">(CGI)</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>A standard definition for an interface between a web server and an
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive external program that allows the external program to service requests.
fb77c505254b6e9c925e23e734463e87574f8f40kess The interface was originally defined by <a
6b64034fa2a644ba291c484c0c01c7df5b8d982ckess href="http://hoohoo.ncsa.uiuc.edu/cgi/overview.html">NCSA</a> but there
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive is also an <a href="http://www.w3.org/CGI/">RFC project</a>.<br />
fb77c505254b6e9c925e23e734463e87574f8f40kess See: <a href="howto/cgi.html">Dynamic Content with CGI</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive id="configurationdirective">Configuration Directive</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>See: <glossary ref="directive">Directive</glossary></dd>
fb77c505254b6e9c925e23e734463e87574f8f40kess <dt><a name="configurationfile" id="configurationfile">Configuration
fb77c505254b6e9c925e23e734463e87574f8f40kess <dd>A text file containing <glossary ref="directive">Directives</glossary>
fb77c505254b6e9c925e23e734463e87574f8f40kess that control the configuration of Apache.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive See: <a href="configuring.html">Configuration Files</a>
130d299c4b2b15be45532a176604c71fdc7bea5bnd <dd>An HTTP <glossary ref="method">method</glossary> for proxying raw data
130d299c4b2b15be45532a176604c71fdc7bea5bnd channels over HTTP. It can be used to encapsulate other protocols, such as
130d299c4b2b15be45532a176604c71fdc7bea5bnd the SSL protocol.
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd <dd>An area in the <glossary ref="configurationfile">configuration
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive ref="directive">directives</glossary> are allowed.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive See: <a href="mod/directive-dict.html#Context">Terms Used to Describe
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive Apache Directives</a>
003f0c9fda6664daf5092a0e42f65ede20098153slive <dt><a name="digitalsignature" id="digitalsignature">Digital
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>An encrypted text block that validates a certificate or other file. A
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <glossary ref="certificationauthority">Certification Authority</glossary>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive creates a signature by generating a hash of the <em>Public Key</em>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive embedded in a <em>Certificate</em>, then encrypting the hash with its own
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <em>Private Key</em>. Only the CA's public key can decrypt the signature,
313bb560bc5c323cfd40c9cad7335b4b8e060aedkess verifying that the CA has authenticated the network entity that owns the
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="directive" id="directive">Directive</a></dt>
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd <dd>A configuration command that controls one or more aspects of Apache's
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd behavior. Directives are placed in the <glossary
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd ref="configurationfile">Configuration File</glossary><br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive See: <a href="mod/directives.html">Directive Index</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="dynamicsharedobject" id="dynamicsharedobject">Dynamic
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive Shared Object</a> <a name="dso" id="dso">(DSO)</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd><glossary ref="module">Modules</glossary> compiled separately from the
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive Apache <program>httpd</program> binary that can be loaded on-demand.<br />
130d299c4b2b15be45532a176604c71fdc7bea5bnd See: <a href="dso.html">Dynamic Shared Object Support</a>
130d299c4b2b15be45532a176604c71fdc7bea5bnd <dt><a name="environmentvariable" id="environmentvariable">Environment
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd <dd>Named variables managed by the operating system shell and used to store
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive information and communicate between programs. Apache also contains
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive internal variables that are referred to as environment variables, but are
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive stored in internal Apache structures, rather than in the shell
1a3f62ca37273a15a06bb94a61d3c6fcf4bf38c9rbowen environment.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive See: <a href="env.html">Environment Variables in Apache</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="export-crippled" id="export-crippled">Export-Crippled</a></dt>
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding <dd>Diminished in cryptographic strength (and security) in order to comply
684f2a9a422185adda0692a1203c5ad6687fc5c5nd with the United States' Export Administration Regulations (EAR).
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd Export-crippled cryptographic software is limited to a small key size,
530eba85dbd41b8a0fa5255d3648d1440199a661slive resulting in <em>Ciphertext</em> which usually can be decrypted by brute
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive force.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>A process that is applied to data that is sent or received by the
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding server. Input filters process data sent by the client to the server,
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding while output filters process documents on the server before they are sent
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding to the client. For example, the <code>INCLUDES</code> output filter
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding id="fully-qualifieddomain-name">Fully-Qualified Domain-Name</a>
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding <dd>The unique name of a network entity, consisting of a hostname and a
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding domain name that can resolve to an IP address. For example,
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <code>www</code> is a hostname, <code>example.com</code> is a domain name,
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd and <code>www.example.com</code> is a fully-qualified domain name.
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding <dt><a name="handler" id="handler">Handler</a></dt>
684f2a9a422185adda0692a1203c5ad6687fc5c5nd <dd>An internal Apache representation of the action to be performed when a
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding file is called. Generally, files have implicit handlers, based on the file
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding type. Normally, all files are simply served by the server, but certain
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding file types are "handled" separately. For example, the
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding <code>cgi-script</code> handler designates files to be processed as
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding See: <a href="handler.html">Apache's Handler Use</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>A mathematical one-way, irreversible algorithm generating a string with
843a03fe0b138a4c1f64cb90a014e9417ac30691fielding fixed-length from another string of any length. Different input strings
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive will usually produce different hashes (depending on the hash function).
58699879a562774640b95e9eedfd891f336e38c2nd <dd>The part of the <glossary ref="http">HTTP</glossary> request and
fb77c505254b6e9c925e23e734463e87574f8f40kess response that is sent before the actual content, and that contains
fb77c505254b6e9c925e23e734463e87574f8f40kess meta-information describing the content.
58699879a562774640b95e9eedfd891f336e38c2nd <dd>A <glossary ref="configurationfile">configuration file</glossary> that
58699879a562774640b95e9eedfd891f336e38c2nd is placed inside the web tree and applies configuration <glossary
58699879a562774640b95e9eedfd891f336e38c2nd ref="directive">directives</glossary> to the directory where it is
58699879a562774640b95e9eedfd891f336e38c2nd placed and all sub-directories. Despite its name, this file can hold
58699879a562774640b95e9eedfd891f336e38c2nd almost any type of directive, not just access-control directives.<br />
fb77c505254b6e9c925e23e734463e87574f8f40kess <dt><a name="httpd.conf" id="httpd.conf">httpd.conf</a></dt>
fb77c505254b6e9c925e23e734463e87574f8f40kess <dd>The main Apache <glossary ref="configurationfile">configuration
fb77c505254b6e9c925e23e734463e87574f8f40kess file</glossary>. The default location is
fb77c505254b6e9c925e23e734463e87574f8f40kess <code>/usr/local/apache2/conf/httpd.conf</code>, but it may be moved using
fb77c505254b6e9c925e23e734463e87574f8f40kess run-time or compile-time configuration.<br />
58699879a562774640b95e9eedfd891f336e38c2nd id="hypertexttransferprotocol">HyperText Transfer Protocol</a>
6b64034fa2a644ba291c484c0c01c7df5b8d982ckess <dd>The standard transmission protocol used on the World Wide Web. Apache
58699879a562774640b95e9eedfd891f336e38c2nd implements version 1.1 of the protocol, referred to as HTTP/1.1 and
6b64034fa2a644ba291c484c0c01c7df5b8d982ckess defined by <a href="http://ietf.org/rfc/rfc2616.txt">RFC 2616</a>.
fb77c505254b6e9c925e23e734463e87574f8f40kess <dd>The HyperText Transfer Protocol (Secure), the standard encrypted
fb77c505254b6e9c925e23e734463e87574f8f40kess communication mechanism on the World Wide Web. This is actually just HTTP
58699879a562774640b95e9eedfd891f336e38c2nd <dd>In the context of <glossary ref="http">HTTP</glossary>, an action to
58699879a562774640b95e9eedfd891f336e38c2nd perform on a resource, specified on the request line by the client. Some
58699879a562774640b95e9eedfd891f336e38c2nd of the methods available in HTTP are <code>GET</code>, <code>POST</code>,
4a7affccb2f1f5b94cab395e1bf3825aed715ebcnd <dt><a name="messagedigest" id="messagedigest">Message Digest</a></dt>
9b5e2c5e769dc678a1aca06df75c32022b2f1492trawick <dd>A hash of a message, which can be used to verify that the contents of
6b64034fa2a644ba291c484c0c01c7df5b8d982ckess the message have not been altered in transit.<br />
4a7affccb2f1f5b94cab395e1bf3825aed715ebcnd <dt><a name="mime-type" id="mime-type">MIME-type</a></dt>
4a7affccb2f1f5b94cab395e1bf3825aed715ebcnd <dd>A way to describe the kind of document being transmitted. Its name
9b5e2c5e769dc678a1aca06df75c32022b2f1492trawick comes from that fact that its format is borrowed from the Multipurpose
4a7affccb2f1f5b94cab395e1bf3825aed715ebcnd Internet Mail Extensions. It consists of a major type and a minor type,
4a7affccb2f1f5b94cab395e1bf3825aed715ebcnd separated by a slash. Some examples are <code>text/html</code>,
4a7affccb2f1f5b94cab395e1bf3825aed715ebcnd <code>image/gif</code>, and <code>application/octet-stream</code>. In
4a7affccb2f1f5b94cab395e1bf3825aed715ebcnd HTTP, the MIME-type is transmitted in the <code>Content-Type</code>
58699879a562774640b95e9eedfd891f336e38c2nd <dd>An independent part of a program. Much of Apache's functionality is
4a7affccb2f1f5b94cab395e1bf3825aed715ebcnd contained in modules that you can choose to include or exclude. Modules
58699879a562774640b95e9eedfd891f336e38c2nd that are compiled into the Apache <program>httpd</program> binary are
58699879a562774640b95e9eedfd891f336e38c2nd called <dfn>static modules</dfn>, while modules that are stored
77ead9e0262e4f08ec336d1a65b2edef7705c839nd separately and can be optionally loaded at run-time are called
77ead9e0262e4f08ec336d1a65b2edef7705c839nd <dfn>dynamic modules</dfn> or <glossary ref="dso">DSOs</glossary>.
9583adab6bc4b3758e41963c905d9dad9f067131nd Modules that are included by default
77ead9e0262e4f08ec336d1a65b2edef7705c839nd are called <dfn>base modules</dfn>. Many modules are available for Apache
77ead9e0262e4f08ec336d1a65b2edef7705c839nd that are not distributed as part of the Apache HTTP Server <glossary
77ead9e0262e4f08ec336d1a65b2edef7705c839nd ref="tarball">tarball</glossary>. These are referred to as
77ead9e0262e4f08ec336d1a65b2edef7705c839nd <dt><a name="modulemagicnumber" id="modulemagicnumber">Module Magic
77ead9e0262e4f08ec336d1a65b2edef7705c839nd <dd>Module Magic Number is a constant defined in the Apache source code that
77ead9e0262e4f08ec336d1a65b2edef7705c839nd is associated with binary compatibility of modules. It is changed when
77ead9e0262e4f08ec336d1a65b2edef7705c839nd internal Apache structures, function calls and other significant parts of
77ead9e0262e4f08ec336d1a65b2edef7705c839nd API change in such a way that binary compatibility cannot be guaranteed
77ead9e0262e4f08ec336d1a65b2edef7705c839nd any more. On MMN change, all third party modules have to be at least
77ead9e0262e4f08ec336d1a65b2edef7705c839nd recompiled, sometimes even slightly changed in order to work with the new
77ead9e0262e4f08ec336d1a65b2edef7705c839nd version of Apache.
77ead9e0262e4f08ec336d1a65b2edef7705c839nd See <a href="http://www.openssl.org/">http://www.openssl.org/</a>#
77ead9e0262e4f08ec336d1a65b2edef7705c839nd <dt><a name="passphrase" id="passphrase">Pass Phrase</a></dt>
77ead9e0262e4f08ec336d1a65b2edef7705c839nd <dd>The word or phrase that protects private key files. It prevents
77ead9e0262e4f08ec336d1a65b2edef7705c839nd unauthorized users from encrypting them. Usually it's just the secret
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd <dt><a name="plaintext" id="plaintext">Plaintext</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="privatekey" id="privatekey">Private Key</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>The secret key in a <glossary ref="publickeycryptography">Public Key
fb77c505254b6e9c925e23e734463e87574f8f40kess Cryptography</glossary> system, used to decrypt incoming messages and
fb77c505254b6e9c925e23e734463e87574f8f40kess sign outgoing ones.<br />
10673857794a4b3d9568ca2d983722a87ed352f1rbowen <dd>An intermediate server that sits between the client and the <em>origin
fb77c505254b6e9c925e23e734463e87574f8f40kess server</em>. It accepts requests from clients, transmits those requests
b12b918ae6baf9c5762ed61b7393d0e2198378c0nd on to the origin server, and then returns the response from the origin
b12b918ae6baf9c5762ed61b7393d0e2198378c0nd server to the client. If several clients request the same content, the
b12b918ae6baf9c5762ed61b7393d0e2198378c0nd proxy can deliver that content from its cache, rather than requesting it
b12b918ae6baf9c5762ed61b7393d0e2198378c0nd from the origin server each time, thereby reducing response time.<br />
fb77c505254b6e9c925e23e734463e87574f8f40kess <dt><a name="publickey" id="publickey">Public Key</a></dt>
fb77c505254b6e9c925e23e734463e87574f8f40kess ref="publickeycryptography">Public Key Cryptography</glossary> system,
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive used to encrypt messages bound for its owner and to decrypt signatures
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive made by its owner.<br />
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd id="publickeycryptography">Public Key Cryptography</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>The study and application of asymmetric encryption systems, which use
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive one key for encryption and another for decryption. A corresponding pair of
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive such keys constitutes a key pair. Also called Asymmetric Cryptography.
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="regularexpresion" id="regularexpresion">Regular Expression</a>
1f53e295ebd19aed1767d12da7abfab9936c148cjerenkrantz <dd>A way of describing a pattern in text - for example, "all the words that
9ed9eaf871c58d281af02e76125ceadb5060afa5nd begin with the letter A" or "every 10-digit phone number" or even "Every
313bb560bc5c323cfd40c9cad7335b4b8e060aedkess sentence with two commas in it, and no capital letter Q". Regular
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive expressions are useful in Apache because they let you apply certain
1f53e295ebd19aed1767d12da7abfab9936c148cjerenkrantz attributes against collections of files or resources in very flexible ways
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive - for example, all .gif and .jpg files under any "images" directory could
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive be written as "<code>/images/.*(jpg|gif)$</code>". Apache uses Perl
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive Compatible Regular Expressions provided by the <a
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive href="http://www.pcre.org/">PCRE</a> library. You can find more documentation
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive about PCRE's regular expression syntax at that site, or at
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <a href="http://en.wikipedia.org/wiki/PCRE">Wikipedia</a>.
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="reverseproxy" id="reverseproxy">Reverse Proxy</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>A <glossary ref="proxy">proxy</glossary> server that appears to the client
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive as if it is an <em>origin server</em>. This is useful to hide the real
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive origin server from the client for security reasons, or to load balance.
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="securesocketslayer" id="securesocketslayer">Secure Sockets
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>A protocol created by Netscape Communications Corporation for general
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive communication authentication and encryption over TCP/IP networks. The most
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive popular usage is <em>HTTPS</em>, i.e. the HyperText Transfer Protocol (HTTP)
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive over SSL.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="servernameindication" id="servernameindication">Server Name
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>An SSL function that allows passing the desired server
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive hostname in the initial SSL handshake message, so that the web
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive server can select the correct virtual host configuration to use
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive in processing the SSL handshake. It was added to SSL starting
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive with the TLS extensions, RFC 3546. <br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive and <a href="http://www.ietf.org/rfc/rfc3546.txt">RFC 3546</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="serversideincludes" id="serversideincludes">Server Side
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>A technique for embedding processing directives inside HTML files.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive See: <a href="howto/ssi.html">Introduction to Server Side Includes</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>The context information of a communication in general.</dd>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>The original SSL/TLS implementation library developed by Eric A.
103a93c625bcde1a6a7a5155b64dcda36f612180pquerna <dt><a name="symmetriccryptophraphy" id="symmetriccryptophraphy">Symmetric
f23fb63b05f89f47d7a3099491f2c68dcce432e9kess <dd>The study and application of <em>Ciphers</em> that use a single secret key
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive for both encryption and decryption operations.<br />
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd <dd>A package of files gathered together using the <code>tar</code> utility.
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd Apache distributions are stored in compressed tar archives or using
b12b918ae6baf9c5762ed61b7393d0e2198378c0nd <dt><a name="transportlayersecurity" id="transportlayersecurity">Transport
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive Layer Security</a> <a name="tls" id="tls">(TLS)</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>The successor protocol to SSL, created by the Internet Engineering Task
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive Force (IETF) for general communication authentication and encryption over
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive TCP/IP networks. TLS version 1 is nearly identical with SSL version 3.<br />
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="uniformresourcelocator" id="uniformresourcelocator">Uniform
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive Resource Locator</a> <a name="url" id="url">(URL)</a></dt>
003f0c9fda6664daf5092a0e42f65ede20098153slive <dd>The name/address of a resource on the Internet. This is the common
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive informal term for what is formally called a <glossary
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd ref="uniformresourceidentifier">Uniform Resource Identifier</glossary>.
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive URLs are usually made up of a scheme, like <code>http</code> or
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <code>https</code>, a hostname, and a path. A URL for this page might
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive be <code>http://httpd.apache.org/docs/&httpd.docs;/glossary.html</code>.
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive id="uniformresourceidentifier">Uniform Resource Identifier</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>A compact string of characters for identifying an abstract or physical
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive resource. It is formally defined by <a
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>. URIs used on the
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive world-wide web are commonly referred to as <glossary
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dt><a name="virtualhosting" id="virtualhosting">Virtual Hosting</a></dt>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>Serving multiple websites using a single instance of Apache. <em>IP
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive virtual hosting</em> differentiates between websites based on their IP
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive address, while <em>name-based virtual hosting</em> uses only the name of the
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd host and can therefore host many sites on the same IP address.<br />
a7f40ca49262952d6dd69d021cf5b0c2b452ae4cnd See: <a href="vhosts/">Apache Virtual Host documentation</a>
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive <dd>An authentication certificate scheme recommended by the International
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive Telecommunication Union (ITU-T) which is used for SSL/TLS authentication.<br
80c4526970a11f37c0f8e3b82afdf03902dac3f3slive</manualpage>