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+<manualpage metafile="glossary.xml.meta">
<title>Glossary</title>
-<summary>
-<p>This glossary defines some of the common terminology related to
-Apache in particular, and web serving in general. More information
-on each concept is provided in the links.</p>
-</summary>
+ <summary>
+ <p>This glossary defines some of the common terminology related to Apache in
+ particular, and web serving in general. More information on each concept
+ is provided in the links.</p>
+ </summary>
<section id="definitions"><title>Definitions</title>
-<dl>
-<dt><a name="authentication">Authentication</a></dt> <dd>The positive
-identification of a network entity such as a server, a client, or a
-user.<br /> See: <a
-href="howto/auth.html">Authentication, Authorization, and Access
-Control</a></dd>
-
-<dt><a name="accesscontrol">Access Control</a></dt>
-<dd>The restriction of access to network realms. In an Apache context
- usually the restriction of access to certain <em>URLs</em>.<br />
-See: <a
-href="howto/auth.html">Authentication, Authorization, and Access
-Control</a></dd>
-
-<dt><a name="algorithm">Algorithm</a></dt>
-<dd>An unambiguous formula or set of rules for solving a problem in
-a finite number of steps. Algorithms for encryption are usually called
-<dfn>Ciphers</dfn>.</dd>
-
-<dt><a name="apacheextensiontool">APache eXtension Tool</a> <a
-name="apxs">(apxs)</a></dt> <dd>A perl script that aids in compiling <a
-href="#module">module</a> sources into Dynamic Shared Objects (<a
-href="#dso">DSO</a>s) and helps install them in the Apache Web
-server.<br /> See: <a
-href="programs/apxs.html">Manual Page: apxs</a></dd>
-
-<dt><a name="certificate">Certificate</a></dt>
-<dd>A data record used for authenticating network entities such
- as a server or a client. A certificate contains X.509 information pieces
- about its owner (called the subject) and the signing <em>Certificate
- Authority</em> (called the issuer), plus the owner's public key and the
- signature made by the CA. Network entities verify these signatures using
- CA certificates.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="certificationauthority">Certification Authority</a> <a
-name="ca">(CA)</a></dt> <dd>A trusted third party whose purpose is to
-sign certificates for network entities it has authenticated using
-secure means. Other network entities can check the signature to verify
-that a CA has authenticated the bearer of a certificate.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="certificatsigningrequest">Certificate Signing Request</a>
-<a name="csr">(CSR)</a></dt> <dd>An unsigned certificate for
-submission to a <em>Certification Authority</em>, which signs it with
-the <em>Private Key</em> of their CA <em>Certificate</em>. Once the
-CSR is signed, it becomes a real certificate.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-
-<dt><a name="cipher">Cipher</a></dt> <dd>An algorithm or system for
-data encryption. Examples are DES, IDEA, RC4, etc.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="ciphertext">Ciphertext</a></dt> <dd>The result after <a
-href="#plaintext">Plaintext</a> is passed through a <a
-href="#cipher">Cipher</a>.<br /> See: <a href="ssl/">SSL/TLS
-Encryption</a></dd>
-
-<dt><a name="commongatewayinterface">Common Gateway Interface</a> <a
-name="cgi">(CGI)</a></dt> <dd>A standard definition for an interface
-between a web server and an external program that allows the external
-program to service requests. The interface was originally defined by
-<a href="http://hoohoo.ncsa.uiuc.edu/cgi/overview.html">NCSA</a> but
-there is also an <a href="http://cgi-spec.golux.com/">RFC
-project</a>.<br />
-See: <a href="howto/cgi.html">Dynamic Content with CGI</a></dd>
-
-
-<dt><a name="configurationdirective">Configuration Directive</a></dt>
-<dd>See: <a href="#directive">Directive</a></dd>
-
-<dt><a name="configurationfile">Configuration File</a></dt>
-<dd>A text file containing <a href="#directive">Directives</a>
-that control the configuration of Apache.<br />
-See: <a href="configuring.html">Configuration Files</a></dd>
-
-<dt><a name="connect">CONNECT</a></dt> <dd>An HTTP <a
-href="#method">method</a> for proxying raw data channels over HTTP. It
-can be used to encapsulate other protocols, such as the SSL
-protocol.</dd>
-
-<dt><a name="context">Context</a></dt> <dd>An area in the <a
-href="#configurationfile">configuration files</a> where certain types
-of <a href="#directive">directives</a> are allowed.<br /> See: <a
-href="mod/directive-dict.html#Context">Terms
-Used to Describe Apache Directives</a></dd>
-
-<dt><a name="digitalsignature">Digital Signature</a></dt>
-<dd>An encrypted text block that validates a certificate or other file. A
- <em>Certification Authority</em> creates a signature by generating a
- hash of the <em>Public Key</em> embedded in a <em>Certificate</em>, then
- encrypting the hash with its own <em>Private Key</em>. Only the CA's
- public key can decrypt the signature, verifying that the CA has
- authenticated the network entity that owns the <em>Certificate</em>.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="directive">Directive</a></dt> <dd>A configuration command
-that controls one or more aspects of Apache's behavior. Directives
-are placed in the <a href="#configurationfile">Configuration
-File</a><br /> See: <a href="mod/directives.html">Directive
-Index</a></dd>
-
-<dt><a name="dynamicsharedobject">Dynamic Shared Object</a> <a
-name="dso">(DSO)</a></dt> <dd><a href="#module">Modules</a> compiled
-seperately from the Apache httpd binary that can be loaded on-demand.<br />
-See: <a href="dso.html">Dynamic Shared Object Support</a></dd>
-
-<dt><a name="environmentvariable">Environment Variable</a> <a
-name="env-variable">(env-variable)</a></dt>
-<dd>Named variables managed by the operating system shell
-and used to store information and communicate between programs. Apache also
-contains internal variables that are referred to as environment variables,
-but are stored in internal Apache structures, rather than in the
-shell environment.<br />
-See: <a href="env.html">Environment Variables in Apache</a></dd>
-
-<dt><a name="export-crippled">Export-Crippled</a></dt>
-<dd>Diminished in cryptographic strength (and security) in order to comply
- with the United States' Export Administration Regulations (EAR).
- Export-crippled cryptographic software is limited to a small key size,
- resulting in <em>Ciphertext</em> which usually can be decrypted by brute
- force.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="filter">Filter</a></dt> <dd>A process that is applied to
-data that is sent or received by the server. Input filters process
-data sent by the client to the server, while output filters process
-documents on the server before they are sent to the client. For
-examle, the <code>INCLUDES</code> output filter processes documents
-for <a href="#ssi">Server Side Includes</a>.<br /> See: <a
-href="filter.html">Filters</a></dd>
-
-<dt><a name="fully-qualifieddomain-name">Fully-Qualified
-Domain-Name</a> <a name="fqdn">(FQDN)</a></dt> <dd>The unique name of
-a network entity, consisting of a hostname and a domain name that can
-resolve to an IP address. For example, <code>www</code> is a hostname,
-<code>example.com</code> is a domain name, and
-<code>www.example.com</code> is a fully-qualified domain name.</dd>
-
-<dt><a name="handler">Handler</a></dt> <dd>An internal Apache
-representation of the action to be performed when a file is
-called. Generally, files have implicit handlers, based on the file
-type. Normally, all files are simply served by the server, but certain
-file types are "handled" separately. For example, the
-<code>cgi-script</code> handler designates files to be processed as <a
-href="#cgi">CGIs</a>.<br />
-See: <a href="handler.html">Apache's Handler Use</a></dd>
-
-<dt><a name="header">Header</a></dt>
-<dd>The part of the <a href="#http">HTTP</a> request and response that
-is sent before the actual content, and that contains meta-information
-describing the content.</dd>
-
-<dt><a name=".htaccess">.htaccess</a></dt> <dd>A <a
-href="#configurationfile">configuration file</a> that is placed inside
-the web tree and applies configuration <a
-href="#directive">directives</a> to the directory where it is placed
-and all sub-directories. Despite its name, this file can hold almost
-any type of directive, not just access-control directives.<br />
-See: <a href="configuring.html">Configuration Files</a></dd>
-
-<dt><a name="httpd.conf">httpd.conf</a></dt>
-<dd>The main Apache <a href="#configurationfile">configuration file</a>.
-The default location is <code>/usr/local/apache2/conf/httpd.conf</code>,
-but it may be moved using run-time or compile-time configuration.<br />
-See: <a href="configuring.html">Configuration Files</a></dd>
-
-<dt><a name="hypertexttransferprotocol">HyperText Transfer
-Protocol</a> <a name="http">(HTTP)</a></dt> <dd>The standard
-transmission protocol used on the World Wide Web. Apache implements
-version 1.1 of the protocol, refered to as HTTP/1.1 and defined by <a
-href="http://ietf.org/rfc/rfc2616.txt">RFC 2616</a>.</dd>
-
-<dt><a name="https">HTTPS</a></dt>
-<dd>The HyperText Transport Protocol (Secure), the standard encrypted
- communication mechanism on the World Wide Web. This is actually just HTTP
- over <a name="ssl">SSL</a>.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="method">Method</a></dt> <dd>In the context of <a
-href="#http">HTTP</a>, an action to perform on a resource, specified
-on the request line by the client. Some of the methods available in
-HTTP are <code>GET</code>, <code>POST</code>, and <code>PUT</code>.</dd>
-
-<dt><a name="messagedigest">Message Digest</a></dt>
-<dd>A hash of a message, which can be used to verify that the contents of
- the message have not been altered in transit.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="mime-type">MIME-type</a></dt> <dd>A way to describe the
-kind of document being transmitted. Its name comes from that fact
-that its format is borrowed from the Multipurpose Internet Mail
-Extensions. It consists of a major type and a minor type, separated
-by a slash. Some examples are <code>text/html</code>,
-<code>image/gif</code>, and <code>application/octet-stream</code>. In
-HTTP, the MIME-type is transmitted in the <code>Content-Type</code> <a
-href="#header">header</a>.<br /> See: <a
-href="mod/mod_mime.html">mod_mime</a></dd>
-
-<dt><a name="module">Module</a></dt> <dd>An independent part of a
-program. Much of Apache's functionality is contained in modules that
-you can choose to include or exclude. Modules that are compiled into
-the the Apache httpd binary are called <em>static modules</em>, while
-modules that are stored seperately and can be optionally loaded at
-run-time are called <em>dynamic modules</em> or <a
-href="#dso">DSOs</a>. Modules that are included by default are called
-<em>base modules</em>. Many modules are available for Apache that are
-not distributed as part of the Apache HTTP Server <a
-href="#tarball">tarball</a>. These are referred to as <em>third-party
-modules</em>.<br />
-See: <a href="mod/">Module Index</a></dd>
-
-<dt><a name="modulemagicnumber">Module Magic Number</a> (<a
-name="mmn">MMN</a>)</dt>
-<dd>
-Module Magic Number is a constant defined in the Apache source code
-that is associated with binary compatibility of modules. It is changed
-when internal Apache structures, function calls and other significant
-parts of API change in such a way that binary compatiblity cannot be
-guaranteed any more. On MMN change, all third party modules have to be
-at least recompiled, sometimes even slightly changed in order to work
-with the new version of Apache.
-</dd>
-
-<dt><a name="openssl">OpenSSL</a></dt>
-<dd>The Open Source toolkit for SSL/TLS<br />
- see <a href="http://www.openssl.org/">http://www.openssl.org/</a></dd>
-
-<dt><a name="passphrase">Pass Phrase</a></dt> <dd>The word or phrase
-that protects private key files. It prevents unauthorized users from
-encrypting them. Usually it's just the secret encryption/decryption
-key used for <a name="cipher">Ciphers</a>.<br /> See: <a
-href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="plaintext">Plaintext</a></dt>
-<dd>The unencrypted text.</dd>
-
-<dt><a name="privatekey">Private Key</a></dt> <dd>The secret key in a
-<a name="publickeycryptography">Public Key Cryptography</a> system,
-used to decrypt incoming messages and sign outgoing ones.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="proxy">Proxy</a></dt> <dd>An intermediate server that
-sits between the client and the <em>origin server</em>. It accepts
-requests from clients, transmits those requests on to the origin
-server, and then returns the response from the origin server to the
-client. If several clients request the same content, the proxy
-can deliver that content from its cache, rather than requesting it
-from the origin server each time, thereby reducing response time.<br />
-See: <a href="mod/mod_proxy.html">mod_proxy</a></dd>
-
-<dt><a name="publickey">Public Key</a></dt> <dd>The publically
-available key in a <a name="publickeycryptography">Public Key
-Cryptography</a> system, used to encrypt messages bound for its owner
-and to decrypt signatures made by its owner.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="publickeycryptography">Public Key Cryptography</a></dt>
-<dd>The study and application of asymmetric encryption systems, which
-use one key for encryption and another for decryption. A corresponding
-pair of such keys constitutes a key pair. Also called Asymmetric
-Crypography.<br /> See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="regularexpresion">Regular Expression</a> <a
-name="regex">(Regex)</a></dt> <dd>A way of
-describing a pattern in text - for example, "all the words that begin with the
-letter A" or "every 10-digit phone number" or even "Every sentence
-with two commas in it, and no capital letter Q". Regular expressions
-are useful in Apache because they let you apply certain
-attributes against collections of files or resources in very flexible
-ways - for example, all .gif and .jpg files under any "images"
-directory could be written as "<code>/images/.*(jpg|gif)$</code>".
-Apache uses Perl Compatible Regular Expressions provided by the
-<a href="http://www.pcre.org/">PCRE</a> library.</dd>
-
-<dt><a name="reverseproxy">Reverse Proxy</a></dt> <dd>A <a
-href="#proxy">proxy</a> server that appears to the client as if it is
-an <em>origin server</em>. This is useful to hide the real origin
-server from the client for security reasons, or to load balance.</dd>
-
-<dt><a name="securesocketslayer">Secure Sockets Layer</a> <a
-name="ssl">(SSL)</a></dt> <dd>A protocol created by Netscape
-Communications Corporation for general communication authentication
-and encryption over TCP/IP networks. The most popular usage is
-<em>HTTPS</em>, i.e. the HyperText Transfer Protocol (HTTP) over SSL.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="serversideincludes">Server Side Includes</a> <a
-name="ssi">(SSI)</a></dt> <dd>A technique for embedding processing
-directives inside HTML files.<br /> See: <a
-href="howto/ssi.html">Introduction to Server Side Includes</a></dd>
-
-<dt><a name="session">Session</a></dt>
-<dd>The context information of a communication in general.</dd>
-
-<dt><a name="ssleay">SSLeay</a></dt>
-<dd>The original SSL/TLS implementation library developed by
- Eric A. Young</dd>
-
-<dt><a name="symmetriccryptophraphy">Symmetric Cryptography</a></dt>
-<dd>The study and application of <em>Ciphers</em> that use a single secret key
- for both encryption and decryption operations.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="tarball">Tarball</a></dt>
-<dd>A package of files gathered together using the <code>tar</code>
-utility. Apache distributions are stored in compressed tar archives
-or using pkzip.</dd>
-
-<dt><a name="transportlayersecurity">Transport Layer Security</a> <a
-name="tls">(TLS)</a></dt> <dd>The successor protocol to SSL, created
-by the Internet Engineering Task Force (IETF) for general
-communication authentication and encryption over TCP/IP networks. TLS
-version 1 and is nearly identical with SSL version 3.<br />
-See: <a href="ssl/">SSL/TLS Encryption</a></dd>
-
-<dt><a name="uniformresourcelocator">Uniform Resource Locator</a> <a
-name="url">(URL)</a></dt> <dd>The name/address of a resource on the
-Internet. This is the common informal term for what is formally
-called a <a href="#uniformresourceidentifier">Uniform Resource
-Identifier</a>. URLs are usually made up of a scheme, like
-<code>http</code> or <code>https</code>, a hostname, and a path. A
-URL for this page is
-<code>http://httpd.apache.org/docs-2.0/glossary.html</code>.</dd>
-
-<dt><a name="uniformresourceidentifier">Uniform Resource Identifier</a> <a
-name="URI">(URI)</a></dt> <dd>A compact string of characters for
-identifying an abstract or physical resource. It is formally defined
-by <a href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>.
-URIs used on the world-wide web are commonly referred to
-as <a href="#url">URLs</a>.</dd>
-
-<dt><a name="virtualhosting">Virtual Hosting</a></dt> <dd>Serving
-multiple websites using a single instance of Apache. <em>IP virtual
-hosting</em> differentiates between websites based on their IP
-address, while <em>name-based virtual hosting</em> uses only the name
-of the host and can therefore host many sites on the same IP
-address.<br /> See: <a href="vhosts/">Apache Virtual Host
-documentation</a></dd>
-
-<dt><a name="x.509">X.509</a></dt> <dd>An authentication certificate
-scheme recommended by the International Telecommunication Union
-(ITU-T) which is used for SSL/TLS authentication.<br /> See: <a
-href="ssl/">SSL/TLS Encryption</a></dd>
-
-</dl>
+ <dl>
+ <dt><a name="accesscontrol" id="accesscontrol">Access Control</a></dt>
+ <dd>The restriction of access to network realms. In an Apache context
+ usually the restriction of access to certain <em>URLs</em>.<br /> See: <a
+ href="howto/auth.html">Authentication, Authorization, and Access
+ Control</a>
+ </dd>
+
+ <dt><a name="algorithm" id="algorithm">Algorithm</a></dt>
+ <dd>An unambiguous formula or set of rules for solving a problem in a finite
+ number of steps. Algorithms for encryption are usually called
+ <dfn>Ciphers</dfn>.
+ </dd>
+
+ <dt><a name="apacheextensiontool" id="apacheextensiontool">APache
+ eXtension Tool</a> <a name="apxs" id="apxs">(apxs)</a></dt>
+ <dd>A perl script that aids in compiling <glossary
+ ref="module">module</glossary> sources into Dynamic Shared Objects
+ (<glossary ref="dso">DSO</glossary>s) and helps install them in the
+ Apache Web server.<br />
+ See: Manual Page: <program>apxs</program>
+ </dd>
+
+ <dt><a name="apacheportableruntime"
+ id="apacheportableruntime">Apache Portable Runtime</a> <a
+ name="apr" id="apr">(APR)</a></dt>
+ <dd>A set of libraries providing many of the basic interfaces
+ between the server and the operating system. APR is developed
+ parallel to the Apache HTTP Server as an independent project.<br />
+ See: <a href="http://apr.apache.org/">Apache Portable Runtime
+ Project</a>
+ </dd>
+
+ <dt><a name="authentication" id="authentication">Authentication</a></dt>
+ <dd>The positive identification of a network entity such as a server, a
+ client, or a user.<br />
+ See: <a href="howto/auth.html">Authentication, Authorization, and Access
+ Control</a>
+ </dd>
+
+ <dt><a name="certificate" id="certificate">Certificate</a></dt>
+ <dd>A data record used for authenticating network entities such
+ as a server or a client. A certificate contains X.509 information pieces
+ about its owner (called the subject) and the signing <glossary
+ ref="certificationauthority">Certification Authority</glossary> (called
+ the issuer), plus the owner's <glossary ref="publickey">public
+ key</glossary> and the
+ signature made by the CA. Network entities verify these signatures
+ using CA certificates.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="certificatsigningrequest"
+ id="certificatsigningrequest">Certificate Signing Request</a>
+ <a name="csr" id="csr">(CSR)</a></dt>
+ <dd>An unsigned <glossary ref="certificate">certificate</glossary> for
+ submission to a <glossary ref="certificationauthority">Certification
+ Authority</glossary>, which signs it with the <glossary
+ ref="privatekey">Private Key</glossary> of their CA
+ <em>Certificate</em>. Once the CSR is signed, it becomes a real
+ certificate.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="certificationauthority"
+ id="certificationauthority">Certification Authority</a>
+ <a name="ca" id="ca">(CA)</a></dt>
+ <dd>A trusted third party whose purpose is to sign certificates for network
+ entities it has authenticated using secure means. Other network entities
+ can check the signature to verify that a CA has authenticated the bearer
+ of a certificate.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="cipher" id="cipher">Cipher</a></dt>
+ <dd>An algorithm or system for data encryption. Examples are DES, IDEA, RC4,
+ etc.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="ciphertext" id="ciphertext">Ciphertext</a></dt>
+ <dd>The result after <glossary ref="plaintext">Plaintext</glossary> is
+ passed through a <glossary ref="cipher">Cipher</glossary>.<br /> See: <a
+ href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="commongatewayinterface" id="commongatewayinterface">Common
+ Gateway Interface</a> <a name="cgi" id="cgi">(CGI)</a></dt>
+ <dd>A standard definition for an interface between a web server and an
+ external program that allows the external program to service requests.
+ There is an <a href="http://www.ietf.org/rfc/rfc3875">Informational
+ RFC</a> which covers the specifics.<br />
+ See: <a href="howto/cgi.html">Dynamic Content with CGI</a>
+ </dd>
+
+ <dt><a name="configurationdirective"
+ id="configurationdirective">Configuration Directive</a></dt>
+ <dd>See: <glossary ref="directive">Directive</glossary></dd>
+
+ <dt><a name="configurationfile" id="configurationfile">Configuration
+ File</a></dt>
+ <dd>A text file containing <glossary ref="directive">Directives</glossary>
+ that control the configuration of Apache.<br />
+ See: <a href="configuring.html">Configuration Files</a>
+ </dd>
+
+ <dt><a name="connect" id="connect">CONNECT</a></dt>
+ <dd>An HTTP <glossary ref="method">method</glossary> for proxying raw data
+ channels over HTTP. It can be used to encapsulate other protocols, such as
+ the SSL protocol.
+ </dd>
+
+ <dt><a name="context" id="context">Context</a></dt>
+ <dd>An area in the <glossary ref="configurationfile">configuration
+ files</glossary> where certain types of <glossary
+ ref="directive">directives</glossary> are allowed.<br />
+ See: <a href="mod/directive-dict.html#Context">Terms Used to Describe
+ Apache Directives</a>
+ </dd>
+
+ <dt><a name="digitalsignature" id="digitalsignature">Digital
+ Signature</a></dt>
+ <dd>An encrypted text block that validates a certificate or other file. A
+ <glossary ref="certificationauthority">Certification Authority</glossary>
+ creates a signature by generating a hash of the <em>Public Key</em>
+ embedded in a <em>Certificate</em>, then encrypting the hash with its own
+ <em>Private Key</em>. Only the CA's public key can decrypt the signature,
+ verifying that the CA has authenticated the network entity that owns the
+ <em>Certificate</em>.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="directive" id="directive">Directive</a></dt>
+ <dd>A configuration command that controls one or more aspects of Apache's
+ behavior. Directives are placed in the <glossary
+ ref="configurationfile">Configuration File</glossary><br />
+ See: <a href="mod/directives.html">Directive Index</a>
+ </dd>
+
+ <dt><a name="dynamicsharedobject" id="dynamicsharedobject">Dynamic
+ Shared Object</a> <a name="dso" id="dso">(DSO)</a></dt>
+ <dd><glossary ref="module">Modules</glossary> compiled separately from the
+ Apache <program>httpd</program> binary that can be loaded on-demand.<br />
+ See: <a href="dso.html">Dynamic Shared Object Support</a>
+ </dd>
+
+ <dt><a name="environmentvariable" id="environmentvariable">Environment
+ Variable</a> <a name="env-variable"
+ id="env-variable">(env-variable)</a></dt>
+ <dd>Named variables managed by the operating system shell and used to store
+ information and communicate between programs. Apache also contains
+ internal variables that are referred to as environment variables, but are
+ stored in internal Apache structures, rather than in the shell
+ environment.<br />
+ See: <a href="env.html">Environment Variables in Apache</a>
+ </dd>
+
+ <dt><a name="export-crippled" id="export-crippled">Export-Crippled</a></dt>
+ <dd>Diminished in cryptographic strength (and security) in order to comply
+ with the United States' Export Administration Regulations (EAR).
+ Export-crippled cryptographic software is limited to a small key size,
+ resulting in <em>Ciphertext</em> which usually can be decrypted by brute
+ force.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="filter" id="filter">Filter</a></dt>
+ <dd>A process that is applied to data that is sent or received by the
+ server. Input filters process data sent by the client to the server,
+ while output filters process documents on the server before they are sent
+ to the client. For example, the <code>INCLUDES</code> output filter
+ processes documents for <glossary ref="ssi">Server Side
+ Includes</glossary>.<br />
+ See: <a href="filter.html">Filters</a>
+ </dd>
+
+ <dt><a name="fully-qualifieddomain-name"
+ id="fully-qualifieddomain-name">Fully-Qualified Domain-Name</a>
+ <a name="fqdn" id="fqdn">(FQDN)</a></dt>
+ <dd>The unique name of a network entity, consisting of a hostname and a
+ domain name that can resolve to an IP address. For example,
+ <code>www</code> is a hostname, <code>example.com</code> is a domain name,
+ and <code>www.example.com</code> is a fully-qualified domain name.
+ </dd>
+
+ <dt><a name="handler" id="handler">Handler</a></dt>
+ <dd>An internal Apache representation of the action to be performed when a
+ file is called. Generally, files have implicit handlers, based on the file
+ type. Normally, all files are simply served by the server, but certain
+ file types are "handled" separately. For example, the
+ <code>cgi-script</code> handler designates files to be processed as
+ <glossary ref="cgi">CGIs</glossary>.<br />
+ See: <a href="handler.html">Apache's Handler Use</a>
+ </dd>
+
+ <dt><a name="hash" id="hash">Hash</a></dt>
+ <dd>A mathematical one-way, irreversible algorithm generating a string with
+ fixed-length from another string of any length. Different input strings
+ will usually produce different hashes (depending on the hash function).
+ </dd>
+
+ <dt><a name="header" id="header">Header</a></dt>
+ <dd>The part of the <glossary ref="http">HTTP</glossary> request and
+ response that is sent before the actual content, and that contains
+ meta-information describing the content.
+ </dd>
+
+ <dt><a name="htaccess" id="htaccess">.htaccess</a></dt>
+ <dd>A <glossary ref="configurationfile">configuration file</glossary> that
+ is placed inside the web tree and applies configuration <glossary
+ ref="directive">directives</glossary> to the directory where it is
+ placed and all sub-directories. Despite its name, this file can hold
+ almost any type of directive, not just access-control directives.<br />
+ See: <a href="configuring.html">Configuration Files</a>
+ </dd>
+
+ <dt><a name="httpd.conf" id="httpd.conf">httpd.conf</a></dt>
+ <dd>The main Apache <glossary ref="configurationfile">configuration
+ file</glossary>. The default location is
+ <code>/usr/local/apache2/conf/httpd.conf</code>, but it may be moved using
+ run-time or compile-time configuration.<br />
+ See: <a href="configuring.html">Configuration Files</a>
+ </dd>
+
+ <dt><a name="hypertexttransferprotocol"
+ id="hypertexttransferprotocol">HyperText Transfer Protocol</a>
+ <a name="http" id="hhtp">(HTTP)</a></dt>
+ <dd>The standard transmission protocol used on the World Wide Web. Apache
+ implements version 1.1 of the protocol, referred to as HTTP/1.1 and
+ defined by <a href="http://ietf.org/rfc/rfc2616.txt">RFC 2616</a>.
+ </dd>
+
+ <dt><a name="https" id="https">HTTPS</a></dt>
+ <dd>The HyperText Transfer Protocol (Secure), the standard encrypted
+ communication mechanism on the World Wide Web. This is actually just HTTP
+ over <glossary ref="ssl">SSL</glossary>.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="method" id="method">Method</a></dt>
+ <dd>In the context of <glossary ref="http">HTTP</glossary>, an action to
+ perform on a resource, specified on the request line by the client. Some
+ of the methods available in HTTP are <code>GET</code>, <code>POST</code>,
+ and <code>PUT</code>.
+ </dd>
+
+ <dt><a name="messagedigest" id="messagedigest">Message Digest</a></dt>
+ <dd>A hash of a message, which can be used to verify that the contents of
+ the message have not been altered in transit.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="mime-type" id="mime-type">MIME-type</a></dt>
+ <dd>A way to describe the kind of document being transmitted. Its name
+ comes from that fact that its format is borrowed from the Multipurpose
+ Internet Mail Extensions. It consists of a major type and a minor type,
+ separated by a slash. Some examples are <code>text/html</code>,
+ <code>image/gif</code>, and <code>application/octet-stream</code>. In
+ HTTP, the MIME-type is transmitted in the <code>Content-Type</code>
+ <glossary ref="header">header</glossary>.<br />
+ See: <a href="mod/mod_mime.html">mod_mime</a>
+ </dd>
+
+ <dt><a name="module" id="module">Module</a></dt>
+ <dd>An independent part of a program. Much of Apache's functionality is
+ contained in modules that you can choose to include or exclude. Modules
+ that are compiled into the Apache <program>httpd</program> binary are
+ called <dfn>static modules</dfn>, while modules that are stored
+ separately and can be optionally loaded at run-time are called
+ <dfn>dynamic modules</dfn> or <glossary ref="dso">DSOs</glossary>.
+ Modules that are included by default
+ are called <dfn>base modules</dfn>. Many modules are available for Apache
+ that are not distributed as part of the Apache HTTP Server <glossary
+ ref="tarball">tarball</glossary>. These are referred to as
+ <dfn>third-party modules</dfn>.<br />
+ See: <a href="mod/">Module Index</a>
+ </dd>
+
+ <dt><a name="modulemagicnumber" id="modulemagicnumber">Module Magic
+ Number</a> (<a name="mmn" id="mmn">MMN</a>)</dt>
+ <dd>Module Magic Number is a constant defined in the Apache source code that
+ is associated with binary compatibility of modules. It is changed when
+ internal Apache structures, function calls and other significant parts of
+ API change in such a way that binary compatibility cannot be guaranteed
+ any more. On MMN change, all third party modules have to be at least
+ recompiled, sometimes even slightly changed in order to work with the new
+ version of Apache.
+ </dd>
+
+ <dt><a name="openssl" id="openssl">OpenSSL</a></dt>
+ <dd>The Open Source toolkit for SSL/TLS<br />
+ See <a href="http://www.openssl.org/">http://www.openssl.org/</a>#
+ </dd>
+
+ <dt><a name="passphrase" id="passphrase">Pass Phrase</a></dt>
+ <dd>The word or phrase that protects private key files. It prevents
+ unauthorized users from encrypting them. Usually it's just the secret
+ encryption/decryption key used for <glossary
+ ref="cipher">Ciphers</glossary>.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="plaintext" id="plaintext">Plaintext</a></dt>
+ <dd>The unencrypted text.</dd>
+
+ <dt><a name="privatekey" id="privatekey">Private Key</a></dt>
+ <dd>The secret key in a <glossary ref="publickeycryptography">Public Key
+ Cryptography</glossary> system, used to decrypt incoming messages and
+ sign outgoing ones.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="proxy" id="proxy">Proxy</a></dt>
+ <dd>An intermediate server that sits between the client and the <em>origin
+ server</em>. It accepts requests from clients, transmits those requests
+ on to the origin server, and then returns the response from the origin
+ server to the client. If several clients request the same content, the
+ proxy can deliver that content from its cache, rather than requesting it
+ from the origin server each time, thereby reducing response time.<br />
+ See: <a href="mod/mod_proxy.html">mod_proxy</a>
+ </dd>
+
+ <dt><a name="publickey" id="publickey">Public Key</a></dt>
+ <dd>The publicly available key in a <glossary
+ ref="publickeycryptography">Public Key Cryptography</glossary> system,
+ used to encrypt messages bound for its owner and to decrypt signatures
+ made by its owner.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="publickeycryptography"
+ id="publickeycryptography">Public Key Cryptography</a></dt>
+ <dd>The study and application of asymmetric encryption systems, which use
+ one key for encryption and another for decryption. A corresponding pair of
+ such keys constitutes a key pair. Also called Asymmetric Cryptography.
+ <br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="regularexpresion" id="regularexpresion">Regular Expression</a>
+ <a name="regex" id="regex">(Regex)</a></dt>
+ <dd>A way of describing a pattern in text - for example, "all the words that
+ begin with the letter A" or "every 10-digit phone number" or even "Every
+ sentence with two commas in it, and no capital letter Q". Regular
+ expressions are useful in Apache because they let you apply certain
+ attributes against collections of files or resources in very flexible ways
+ - for example, all .gif and .jpg files under any "images" directory could
+ be written as "<code>/images/.*(jpg|gif)$</code>". In places where
+ regular expressions are used to replace strings, the special variables
+ $1 ... $9 contain backreferences to the grouped parts (in parentheses) of
+ the matched expression. The special variable $0 contains a backreference
+ to the whole matched expression. To write a literal dollar sign in a
+ replacement string, it can be escaped with a backslash. Historically, the
+ variable & could be used as alias for $0 in some places. This is no
+ longer possible since version 2.3.6. Apache uses Perl Compatible Regular
+ Expressions provided by the <a href="http://www.pcre.org/">PCRE</a>
+ library. You can find more documentation about PCRE's regular expression
+ syntax at that site, or at
+ <a href="http://en.wikipedia.org/wiki/PCRE">Wikipedia</a>.
+ </dd>
+
+ <dt><a name="reverseproxy" id="reverseproxy">Reverse Proxy</a></dt>
+ <dd>A <glossary ref="proxy">proxy</glossary> server that appears to the client
+ as if it is an <em>origin server</em>. This is useful to hide the real
+ origin server from the client for security reasons, or to load balance.
+ </dd>
+
+ <dt><a name="securesocketslayer" id="securesocketslayer">Secure Sockets
+ Layer</a> <a name="ssl" id="ssl">(SSL)</a></dt>
+ <dd>A protocol created by Netscape Communications Corporation for general
+ communication authentication and encryption over TCP/IP networks. The most
+ popular usage is <em>HTTPS</em>, i.e. the HyperText Transfer Protocol (HTTP)
+ over SSL.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="servernameindication" id="servernameindication">Server Name
+ Indication</a> <a name="sni" id="sni">(SNI)</a></dt>
+ <dd>An SSL function that allows passing the desired server
+ hostname in the initial SSL handshake message, so that the web
+ server can select the correct virtual host configuration to use
+ in processing the SSL handshake. It was added to SSL starting
+ with the TLS extensions, RFC 3546. <br />
+ See: <a href="ssl/ssl_faq.html">the SSL FAQ</a>
+ and <a href="http://www.ietf.org/rfc/rfc3546.txt">RFC 3546</a>
+ </dd>
+
+ <dt><a name="serversideincludes" id="serversideincludes">Server Side
+ Includes</a> <a name="ssi" id="ssi">(SSI)</a></dt>
+ <dd>A technique for embedding processing directives inside HTML files.<br />
+ See: <a href="howto/ssi.html">Introduction to Server Side Includes</a>
+ </dd>
+
+ <dt><a name="session" id="session">Session</a></dt>
+ <dd>The context information of a communication in general.</dd>
+
+ <dt><a name="ssleay" id="ssleay">SSLeay</a></dt>
+ <dd>The original SSL/TLS implementation library developed by Eric A.
+ Young
+ </dd>
+
+ <dt><a name="subrequest" id="subrequest">Subrequest</a></dt>
+ <dd>Apache provides a subrequest API to modules that allows other
+ filesystem or URL paths to be partially or fully evaluated by
+ the server. Example consumers of this API are
+ <directive module="mod_dir">DirectoryIndex</directive>,
+ <module>mod_autoindex</module>, and <module>mod_include</module>.
+ </dd>
+
+ <dt><a name="symmetriccryptophraphy" id="symmetriccryptophraphy">Symmetric
+ Cryptography</a></dt>
+ <dd>The study and application of <em>Ciphers</em> that use a single secret key
+ for both encryption and decryption operations.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="tarball" id="tarball">Tarball</a></dt>
+ <dd>A package of files gathered together using the <code>tar</code> utility.
+ Apache distributions are stored in compressed tar archives or using
+ pkzip.
+ </dd>
+
+ <dt><a name="transportlayersecurity" id="transportlayersecurity">Transport
+ Layer Security</a> <a name="tls" id="tls">(TLS)</a></dt>
+ <dd>The successor protocol to SSL, created by the Internet Engineering Task
+ Force (IETF) for general communication authentication and encryption over
+ TCP/IP networks. TLS version 1 is nearly identical with SSL version 3.<br />
+ See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+
+ <dt><a name="uniformresourcelocator" id="uniformresourcelocator">Uniform
+ Resource Locator</a> <a name="url" id="url">(URL)</a></dt>
+ <dd>The name/address of a resource on the Internet. This is the common
+ informal term for what is formally called a <glossary
+ ref="uniformresourceidentifier">Uniform Resource Identifier</glossary>.
+ URLs are usually made up of a scheme, like <code>http</code> or
+ <code>https</code>, a hostname, and a path. A URL for this page might
+ be <code>http://httpd.apache.org/docs/&httpd.docs;/glossary.html</code>.
+ </dd>
+
+ <dt><a name="uniformresourceidentifier"
+ id="uniformresourceidentifier">Uniform Resource Identifier</a>
+ <a name="URI" id="URI">(URI)</a></dt>
+ <dd>A compact string of characters for identifying an abstract or physical
+ resource. It is formally defined by <a
+ href="http://www.ietf.org/rfc/rfc2396.txt">RFC 2396</a>. URIs used on the
+ world-wide web are commonly referred to as <glossary
+ ref="url">URLs</glossary>.
+ </dd>
+
+ <dt><a name="virtualhosting" id="virtualhosting">Virtual Hosting</a></dt>
+ <dd>Serving multiple websites using a single instance of Apache. <em>IP
+ virtual hosting</em> differentiates between websites based on their IP
+ address, while <em>name-based virtual hosting</em> uses only the name of the
+ host and can therefore host many sites on the same IP address.<br />
+ See: <a href="vhosts/">Apache Virtual Host documentation</a>
+ </dd>
+
+ <dt><a name="x.509" id="x.509">X.509</a></dt>
+ <dd>An authentication certificate scheme recommended by the International
+ Telecommunication Union (ITU-T) which is used for SSL/TLS authentication.<br
+ /> See: <a href="ssl/">SSL/TLS Encryption</a>
+ </dd>
+ </dl>
</section>
</manualpage>