Grammar, spelling, and other minor corrections.

    </highlight>

    <p>The default protocol names are <code>https</code> for port 443

       and <code>http</code> for all other ports.  To specify another protocol

       is being used with a listening port, add the <var>protocol</var>

       and <code>http</code> for all other ports.  To specify that another

       protocol is being used with a listening port, add the <var>protocol</var>

       argument to the <directive module="mpm_common">Listen</directive>

       directive.</p>

       sends it to the server. See the

       <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&amp;sektion=9">

       accf_http(9)</a> man page for more details.  Since HTTPS requests are

       encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&amp;sektion=9">

       encrypted, only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&amp;sektion=9">

       accf_data(9)</a> filter is used.</p>

    <p>The default values on Linux are:</p>

</contextlist>

<usage>

    <p>While processing a request the server looks for

    <p>While processing a request, the server looks for

    the first existing configuration file from this list of names in

    every directory of the path to the document, if distributed

    configuration files are <a href="#allowoverride">enabled for that

    <highlight language="config">AccessFileName .acl</highlight>

    <p>before returning the document

    <p>Before returning the document

    <code>/usr/local/web/index.html</code>, the server will read

    <code>/.acl</code>, <code>/usr/.acl</code>,

    <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>

    for directives, unless they have been disabled with</p>

    for directives unless they have been disabled with:</p>

    <highlight language="config">

<Directory "/">

<usage>

    <p>The <directive>AllowEncodedSlashes</directive> directive allows URLs

    which contain encoded path separators (<code>%2F</code> for <code>/</code>

    and additionally <code>%5C</code> for <code>\</code> on according systems)

    and additionally <code>%5C</code> for <code>\</code> on accordant systems)

    to be used in the path info.</p>

    <p>With the default value, <code>Off</code>, such URLs are refused

<usage>

    <p>When the server finds an <code>.htaccess</code> file (as

    specified by <directive module="core">AccessFileName</directive>)

    specified by <directive module="core">AccessFileName</directive>),

    it needs to know which directives declared in that file can override

    earlier configuration directives.</p>

    <p>When this directive is set to <code>None</code> and <directive

    module="core">AllowOverrideList</directive> is set to

    <code>None</code> <a href="#accessfilename">.htaccess</a> files are

    <code>None</code> <a href="#accessfilename">.htaccess</a>, files are

    completely ignored. In this case, the server will not even attempt

    to read <code>.htaccess</code> files in the filesystem.</p>

      <dd>

      Allow use of AllowOverride option to treat syntax errors in

      .htaccess as non-fatal: instead of causing an Internal Server

      .htaccess as nonfatal. Instead of causing an Internal Server

      Error, disallowed or unrecognised directives will be ignored

      and a warning logged:

      <ul>

          <li><strong>Nonfatal=Override</strong> treats directives

              forbidden by AllowOverride as non-fatal.</li>

              forbidden by AllowOverride as nonfatal.</li>

          <li><strong>Nonfatal=Unknown</strong> treats unknown directives

              as non-fatal.  This covers typos and directives implemented

              as nonfatal.  This covers typos and directives implemented

              by a module that's not present.</li>

          <li><strong>Nonfatal=All</strong> treats both the above as non-fatal.</li>

          <li><strong>Nonfatal=All</strong> treats both the above as nonfatal.</li>

      </ul>

      <p>Note that a syntax error in a valid directive will still cause

      an internal server error.</p>

      Allow use of the directives controlling specific directory

      features (<directive module="core">Options</directive> and

      <directive module="mod_include">XBitHack</directive>).

      An equal sign may be given followed by a comma (but no spaces)

      separated lists of options that may be set using the <directive

      An equal sign may be given followed by a comma-separated list, without spaces,

      of options that may be set using the <directive

      module="core">Options</directive> command.

      <note><title>Implicit disabling of Options</title>

    <highlight language="config">AllowOverride AuthConfig Indexes</highlight>

    <p>In the example above all directives that are neither in the group

    <p>In the example above, all directives that are neither in the group

    <code>AuthConfig</code> nor <code>Indexes</code> cause an internal

    server error.</p>

<usage>

    <p>When the server finds an <code>.htaccess</code> file (as

    specified by <directive module="core">AccessFileName</directive>)

    specified by <directive module="core">AccessFileName</directive>),

    it needs to know which directives declared in that file can override

    earlier configuration directives.</p>

AllowOverrideList Redirect RedirectMatch

    </highlight>

    <p>In the example above only the <code>Redirect</code> and

    <p>In the example above, only the <code>Redirect</code> and

    <code>RedirectMatch</code> directives are allowed. All others will

    cause an internal server error.</p>

AllowOverrideList CookieTracking CookieName

    </highlight>

    <p>In the example above <directive module="core">AllowOverride

    <p>In the example above, <directive module="core">AllowOverride

    </directive> grants permission to the <code>AuthConfig</code>

    directive grouping and <directive>AllowOverrideList</directive> grants

    permission to only two directives from the <code>FileInfo</code> directive

    <p><directive>CGIPassAuth</directive> allows scripts access to HTTP

    authorization headers such as <code>Authorization</code>, which is

    required for scripts that implement HTTP Basic authentication.

    Normally these HTTP headers are hidden from scripts, as it allows

    scripts to see user ids and passwords used to access the server when

    Normally these HTTP headers are hidden from scripts. This is to disallow

    scripts from seeing user ids and passwords used to access the server when

    HTTP Basic authentication is enabled in the web server.  This directive

    should be used when scripts are allowed to implement HTTP Basic

    authentication.</p>

    at build time.</p>

   <p>Note: <directive>ServerRoot</directive> should be specified before this

   directive is used, otherwise the default value of <directive>ServerRoot</directive>

   directive is used. Otherwise, the default value of <directive>ServerRoot</directive>

   would be used to set the base directory.</p>

</usage>

    URL in an <code>ErrorDocument 401</code>, the client will not

    know to prompt the user for a password since it will not

    receive the 401 status code. Therefore, <strong>if you use an

    <code>ErrorDocument 401</code> directive then it must refer to a local

    <code>ErrorDocument 401</code> directive, then it must refer to a local

    document.</strong></p>

    <p>Microsoft Internet Explorer (MSIE) will by default ignore

    <highlight language="config">ErrorLog syslog:user</highlight>

    <p>Additional modules can provide their own ErrorLog providers. The syntax

    is similar to the <code>syslog</code> example above.</p>

    <p>SECURITY: See the <a

    href="../misc/security_tips.html#serverroot">security tips</a>

    document for details on why your security could be compromised

    or request. This can be used to correlate which log lines belong to the

    same connection or request, which request happens on which connection.

    A <code>%L</code> format string is also available in

    <module>mod_log_config</module>, to allow to correlate access log entries

    <module>mod_log_config</module> to allow to correlate access log entries

    with error log lines. If <module>mod_unique_id</module> is loaded, its

    unique id will be used as log ID for requests.</p>

<usage>

    <p>This option tracks additional data per worker about the

    currently executing request, and a utilization summary; you

    can see these variables during runtime by configuring

    currently executing request and creates a utilization summary.

    You can see these variables during runtime by configuring

    <module>mod_status</module>.  Note that other modules may

    rely on this scoreboard.</p>

    <p>This setting applies to the entire server, and cannot be

    <p>This setting applies to the entire server and cannot be

    enabled or disabled on a virtualhost-by-virtualhost basis.

    The collection of extended status information can slow down

    the server.  Also note that this setting cannot be changed

    third party modules may do the same.  Such modules rely on

    collecting detailed information about the state of all workers.

    The default is changed by <module>mod_status</module> beginning

    with version 2.3.6; the previous default was always Off.</p>

    with version 2.3.6. The previous default was always Off.</p>

    </note>

</usage>

    changed via <directive>FileETag</directive>.

    </note>

    <note><title>Server Side Includes</title>

    An ETag is not generated for responses parsed by <module>mod_include</module>,

    An ETag is not generated for responses parsed by <module>mod_include</module>

    since the response entity can change without a change of the INode, MTime, or Size

    of the static file with embedded SSI directives.

    </note>

    encoding will be used in order to send content of unknown

    length over persistent connections.</p>

    <p>When a client uses a Keep-Alive connection it will be counted

    <p>When a client uses a Keep-Alive connection, it will be counted

    as a single "request" for the <directive module="mpm_common"

    >MaxConnectionsPerChild</directive> directive, regardless

    of how many requests are sent using the connection.</p>

    <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,

    <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,

    <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is

    case-sensitive.</strong> If <code>GET</code> is used it will also

    case-sensitive.</strong> If <code>GET</code> is used, it will also

    restrict <code>HEAD</code> requests. The <code>TRACE</code> method

    cannot be limited (see <directive module="core"

    >TraceEnable</directive>).</p>

    <p>The directive stores two different limits, which are evaluated on

    per-request basis. The first <var>number</var> is the maximum number of

    internal redirects, that may follow each other. The second <var>number</var>

    determines, how deep subrequests may be nested. If you specify only one

    internal redirects that may follow each other. The second <var>number</var>

    determines how deeply subrequests may be nested. If you specify only one

    <var>number</var>, it will be assigned to both limits.</p>

    <highlight language="config">LimitInternalRecursion 5</highlight>

    attacks.</p>

    <p>If, for example, you are permitting file upload to a particular

    location, and wish to limit the size of the uploaded file to 100K,

    location and wish to limit the size of the uploaded file to 100K,

    you might use the following directive:</p>

    <highlight language="config">LimitRequestBody 102400</highlight>

    <p>The <directive type="section">Location</directive>

    functionality is especially useful when combined with the

    <directive module="core">SetHandler</directive>

    directive. For example, to enable status requests, but allow them

    directive. For example, to enable status requests but allow them

    only from browsers at <code>example.com</code>, you might use:</p>

    <highlight language="config">

    <highlight language="config">LogLevel notice</highlight>

    <note><title>Note</title>

      <p>When logging to a regular file messages of the level

      <p>When logging to a regular file, messages of the level

      <code>notice</code> cannot be suppressed and thus are always

      logged. However, this doesn't apply when logging is done

      using <code>syslog</code>.</p>

    <p>The <directive>Mutex</directive> directive sets the mechanism,

    and optionally the lock file location, that httpd and modules use

    to serialize access to resources.  Specify <code>default</code> as

    the first argument to change the settings for all mutexes; specify

    a mutex name (see table below) as the first argument to override

    the second argument to change the settings for all mutexes; specify

    a mutex name (see table below) as the second argument to override

    defaults only for that mutex.</p>

    <p>The <directive>Mutex</directive> directive is typically used in

    on a NFS- or AFS-filesystem.  The basename of the file will be the mutex

    type, an optional instance string provided by the module, and unless the

    <code>OmitPID</code> keyword is specified, the process id of the httpd

    parent process will be appended to to make the file name unique, avoiding

    parent process will be appended to make the file name unique, avoiding

    conflicts when multiple httpd instances share a lock file directory.  For

    example, if the mutex name is <code>mpm-accept</code> and the lock file

    directory is <code>/var/httpd/locks</code>, the lock file name for the

      <dt><code>Indexes</code></dt>

      <dd>

      If a URL which maps to a directory is requested, and there

      If a URL which maps to a directory is requested and there

      is no <directive module="mod_dir">DirectoryIndex</directive>

      (<em>e.g.</em>, <code>index.html</code>) in that directory, then

      <module>mod_autoindex</module> will return a formatted listing

    <note><title>Note</title>

    <p>Mixing <directive>Options</directive> with a <code>+</code> or

    <code>-</code> with those without is not valid syntax, and will be

    <code>-</code> with those without is not valid syntax and will be

    rejected during server startup by the syntax check with an abort.</p>

    </note>

<syntax>Protocol <var>protocol</var></syntax>

<contextlist><context>server config</context><context>virtual host</context></contextlist>

<compatibility>Available in Apache 2.1.5 and later.

On Windows from Apache 2.3.3 and later.</compatibility>

On Windows, from Apache 2.3.3 and later.</compatibility>

<usage>

    <p>This directive specifies the protocol used for a specific listening socket.

       The protocol is used to determine which module should handle a request, and

       The protocol is used to determine which module should handle a request and

       to apply protocol specific optimizations with the <directive>AcceptFilter</directive>

       directive.</p>

    <p>You only need to set the protocol if you are running on non-standard ports, otherwise <code>http</code> is assumed for port 80 and <code>https</code> for port 443.</p>

    <p>You only need to set the protocol if you are running on non-standard ports;

       otherwise, <code>http</code> is assumed for port 80 and <code>https</code>

       for port 443.</p>

    <p>For example, if you are running <code>https</code> on a non-standard port, specify the protocol explicitly:</p>

    or <code>max</code> to indicate to the server that the limit should

    be set to the maximum allowed by the operating system

    configuration. Raising the maximum resource limit requires that

    the server is running as <code>root</code>, or in the initial startup

    the server is running as <code>root</code> or in the initial startup

    phase.</p>

    <p>This applies to processes forked off from Apache httpd children

    <p>This applies to processes forked from Apache httpd children

    servicing requests, not the Apache httpd children themselves. This

    includes CGI scripts and SSI exec commands, but not any

    processes forked off from the Apache httpd parent such as piped

    processes forked from the Apache httpd parent, such as piped

    logs.</p>

    <p>CPU resource limits are expressed in seconds per

    or <code>max</code> to indicate to the server that the limit should

    be set to the maximum allowed by the operating system

    configuration. Raising the maximum resource limit requires that

    the server is running as <code>root</code>, or in the initial startup

    the server is running as <code>root</code> or in the initial startup

    phase.</p>

    <p>This applies to processes forked off from Apache httpd children

    <p>This applies to processes forked from Apache httpd children

    servicing requests, not the Apache httpd children themselves. This

    includes CGI scripts and SSI exec commands, but not any

    processes forked off from the Apache httpd parent such as piped

    processes forked from the Apache httpd parent, such as piped

    logs.</p>

    <p>Memory resource limits are expressed in bytes per

<usage>

    <p>Takes 1 or 2 parameters. The first parameter sets the soft

    resource limit for all processes and the second parameter sets

    resource limit for all processes, and the second parameter sets

    the maximum resource limit. Either parameter can be a number,

    or <code>max</code> to indicate to the server that the limit

    should be set to the maximum allowed by the operating system

    configuration. Raising the maximum resource limit requires that

    the server is running as <code>root</code>, or in the initial startup

    the server is running as <code>root</code> or in the initial startup

    phase.</p>

    <p>This applies to processes forked off from Apache httpd children

    <p>This applies to processes forked from Apache httpd children

    servicing requests, not the Apache httpd children themselves. This

    includes CGI scripts and SSI exec commands, but not any

    processes forked off from the Apache httpd parent such as piped

    processes forked from the Apache httpd parent, such as piped

    logs.</p>

    <p>Process limits control the number of processes per user.</p>

    <code>minimal</code> is not recommended because it makes it more

    difficult to debug interoperational problems. Also note that

    disabling the Server: header does nothing at all to make your

    server more secure; the idea of "security through obscurity"

    server more secure. The idea of "security through obscurity"

    is a myth and leads to a false sense of safety.</note>

</usage>

    <note><title>Note</title>

    <p>Despite claims to the contrary, <code>TRACE</code> is not

    a security vulnerability and there is no viable reason for

    a security vulnerability, and there is no viable reason for

    it to be disabled. Doing so necessarily makes your server

    non-compliant.</p>

    noncompliant.</p>

    </note>

</usage>

</directivesynopsis>

    <p>This directive can be used to toggle the use of <directive module="core"

    type="section">IfDefine</directive> sections without needing to alter

    <code>-D</code> arguments in any startup scripts.</p>

    <p>While this directive is supported in virtual host context,

       the changes it makes are visible to any later configuration

       directives, beyond any enclosing virtual host.</p>

</usage>

</directivesynopsis>

    the client if any are supplied (otherwise it will use the

    canonical name, as defined above). These values are the same

    that are used to implement <a

    href="../vhosts/name-based.html">name-based virtual hosts</a>,

    href="../vhosts/name-based.html">name-based virtual hosts</a>

    and are available with the same clients. The CGI variables

    <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be

    constructed from the client supplied values as well.</p>

    <p>An example where this may be useful is on an intranet server

    where you have users connecting to the machine using short

    names such as <code>www</code>. You'll notice that if the users

    type a shortname, and a URL which is a directory, such as

    type a shortname and a URL which is a directory, such as

    <code>http://www/splat</code>, <em>without the trailing

    slash</em> then Apache httpd will redirect them to

    slash</em>, then Apache httpd will redirect them to

    <code>http://www.example.com/splat/</code>. If you have

    authentication enabled, this will cause the user to have to

    authenticate twice (once for <code>www</code> and once again

    <p>There is a third option, <code>UseCanonicalName DNS</code>,

    which is intended for use with mass IP-based virtual hosting to

    support ancient clients that do not provide a

    <code>Host:</code> header. With this option Apache httpd does a

    <code>Host:</code> header. With this option, Apache httpd does a

    reverse DNS lookup on the server IP address that the client

    connected to in order to work out self-referential URLs.</p>

    <note type="warning"><title>Warning</title>

    <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>

    <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>,

    they may be broken by this option. The client is essentially free

    to give whatever value they want as a hostname. But if the CGI is

    only using <code>SERVER_NAME</code> to construct self-referential URLs

    only using <code>SERVER_NAME</code> to construct self-referential URLs,

    then it should be just fine.</p>

    </note>

</usage>

<usage>

    <p>In many situations Apache httpd must construct a <em>self-referential</em>

    URL -- that is, a URL that refers back to the same server. With

    <code>UseCanonicalPhysicalPort On</code> Apache httpd will, when

    <code>UseCanonicalPhysicalPort On</code>, Apache httpd will, when

    constructing the canonical port for the server to honor

    the <directive module="core">UseCanonicalName</directive> directive,

    provide the actual physical port number being used by this request

    as a potential port. With <code>UseCanonicalPhysicalPort Off</code>

    as a potential port. With <code>UseCanonicalPhysicalPort Off</code>,

    Apache httpd will not ever use the actual physical port number, instead

    relying on all configured information to construct a valid port number.</p>

    </highlight>

    <p>Each Virtual Host must correspond to a different IP address,

    different port number or a different host name for the server,

    different port number, or a different host name for the server,

    in the former case the server machine must be configured to

    accept IP packets for multiple addresses. (If the machine does

    not have multiple network interfaces, then this can be

    requested hostname.  If no matching name-based virtual host is found,

    then the first listed virtual host that matched the IP address will be

    used.  As a consequence, the first listed virtual host for a given IP address

    and port combination is default virtual host for that IP and port

    and port combination is the default virtual host for that IP and port

    combination.</p>

    <note type="warning"><title>Security</title>

<directivesynopsis>

<name>MergeTrailers</name>

<description>Determins whether trailers are merged into headers</description>

<description>Determines whether trailers are merged into headers</description>

<syntax>MergeTrailers [on|off]</syntax>

<default>MergeTrailers off</default>

<contextlist><context>server config</context><context>virtual host</context></contextlist>

<compatibility>2.4.10 and later</compatibility>

<compatibility>2.4.11 and later</compatibility>

<usage>

    <p>This directive controls whether HTTP trailers are copied into the

    internal representation of HTTP headers. This mergeing occurs when the 

    internal representation of HTTP headers. This merging occurs when the 

    request body has been completely consumed, long after most header 

    processing would have a chance to examine or modify request headers.</p>

    <p>This option is provided for compatibility with releases prior to 2.4.10,

    <p>This option is provided for compatibility with releases prior to 2.4.11,

    where trailers were always merged.</p>

</usage>

</directivesynopsis>