path: root/docs/manual/mod/mod_access_compat.xml

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<modulesynopsis metafile="mod_access_compat.xml.meta">

<name>mod_access_compat</name>
<description>Group authorizations based on host (name or IP
address)</description>
<status>Extension</status>
<sourcefile>mod_access_compat.c</sourcefile>
<identifier>access_compat_module</identifier>
<compatibility>Available in Apache HTTP Server 2.3 as a compatibility module with
previous versions of Apache httpd 2.x.  The directives provided by this module
have been deprecated by the new authz refactoring.  Please see
<module>mod_authz_host</module></compatibility>

<summary>
    <p>The directives provided by <module>mod_access_compat</module> are
    used in <directive module="core" type="section">Directory</directive>,
    <directive module="core" type="section">Files</directive>, and
    <directive module="core" type="section">Location</directive> sections
    as well as <code><a href="core.html#accessfilename">.htaccess</a>
    </code> files to control access to particular parts of the server.
    Access can be controlled based on the client hostname, IP address, or
    other characteristics of the client request, as captured in <a
    href="../env.html">environment variables</a>. The <directive
    module="mod_access_compat">Allow</directive> and <directive
    module="mod_access_compat">Deny</directive> directives are used to
    specify which clients are or are not allowed access to the server,
    while the <directive module="mod_access_compat">Order</directive>
    directive sets the default access state, and configures how the
    <directive module="mod_access_compat">Allow</directive> and <directive
    module="mod_access_compat">Deny</directive> directives interact with each
    other.</p>

    <p>Both host-based access restrictions and password-based
    authentication may be implemented simultaneously. In that case,
    the <directive module="mod_access_compat">Satisfy</directive> directive is used
    to determine how the two sets of restrictions interact.</p>

    <note type="warning"><title>Note</title>
      <p>The directives provided by <module>mod_access_compat</module> have
      been deprecated by the new authz refactoring. Please see
      <module>mod_authz_host</module>.</p>
    </note>

    <p>In general, access restriction directives apply to all
    access methods (<code>GET</code>, <code>PUT</code>,
    <code>POST</code>, etc). This is the desired behavior in most
    cases. However, it is possible to restrict some methods, while
    leaving other methods unrestricted, by enclosing the directives
    in a <directive module="core" type="section">Limit</directive> section.</p>
</summary>

<seealso><directive module="mod_authz_core">Require</directive></seealso>
<seealso><module>mod_authz_host</module></seealso>
<seealso><module>mod_authz_core</module></seealso>

<directivesynopsis>
<name>Allow</name>
<description>Controls which hosts can access an area of the
server</description>
<syntax> Allow from all|<var>host</var>|env=[!]<var>env-variable</var>
[<var>host</var>|env=[!]<var>env-variable</var>] ...</syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>Limit</override>

<usage>
    <p>The <directive>Allow</directive> directive affects which hosts can
    access an area of the server. Access can be controlled by
    hostname, IP address, IP address range, or by other
    characteristics of the client request captured in environment
    variables.</p>

    <p>The first argument to this directive is always
    <code>from</code>. The subsequent arguments can take three
    different forms. If <code>Allow from all</code> is specified, then
    all hosts are allowed access, subject to the configuration of the
    <directive module="mod_access_compat">Deny</directive> and <directive
    module="mod_access_compat">Order</directive> directives as discussed
    below. To allow only particular hosts or groups of hosts to access
    the server, the <em>host</em> can be specified in any of the
    following formats:</p>

    <dl>
      <dt>A (partial) domain-name</dt>

      <dd>
      <example><title>Example:</title>
        Allow from example.org<br />
        Allow from .net example.edu
      </example>
      <p>Hosts whose names match, or end in, this string are allowed
      access. Only complete components are matched, so the above
      example will match <code>foo.example.org</code> but it will not
      match <code>fooexample.org</code>. This configuration will cause
      Apache httpd to perform a double DNS lookup on the client IP
      address, regardless of the setting of the <directive
      module="core">HostnameLookups</directive> directive.  It will do
      a reverse DNS lookup on the IP address to find the associated
      hostname, and then do a forward lookup on the hostname to assure
      that it matches the original IP address.  Only if the forward
      and reverse DNS are consistent and the hostname matches will
      access be allowed.</p></dd>

      <dt>A full IP address</dt>

      <dd>
      <example><title>Example:</title>
        Allow from 10.1.2.3<br />
        Allow from 192.168.1.104 192.168.1.205
      </example>
      <p>An IP address of a host allowed access</p></dd>

      <dt>A partial IP address</dt>

      <dd>
      <example><title>Example:</title>
        Allow from 10.1<br />
        Allow from 10 172.20 192.168.2
      </example>
      <p>The first 1 to 3 bytes of an IP address, for subnet
      restriction.</p></dd>

      <dt>A network/netmask pair</dt>

      <dd>
      <example><title>Example:</title>
        Allow from 10.1.0.0/255.255.0.0
      </example>
      <p>A network a.b.c.d, and a netmask w.x.y.z. For more
      fine-grained subnet restriction.</p></dd>

      <dt>A network/nnn CIDR specification</dt>

      <dd>
      <example><title>Example:</title>
        Allow from 10.1.0.0/16
      </example>
      <p>Similar to the previous case, except the netmask consists of
      nnn high-order 1 bits.</p></dd>
    </dl>

    <p>Note that the last three examples above match exactly the
    same set of hosts.</p>

    <p>IPv6 addresses and IPv6 subnets can be specified as shown
    below:</p>

    <example>
       Allow from 2001:db8::a00:20ff:fea7:ccea<br />
       Allow from 2001:db8::a00:20ff:fea7:ccea/10
    </example>

    <p>The third format of the arguments to the
    <directive>Allow</directive> directive allows access to the server
    to be controlled based on the existence of an <a
    href="../env.html">environment variable</a>. When <code>Allow from
    env=<var>env-variable</var></code> is specified, then the request is
    allowed access if the environment variable <var>env-variable</var>
    exists. When <code>Allow from env=!<var>env-variable</var></code> is
    specified, then the request is allowed access if the environment
    variable <var>env-variable</var> doesn't exist.
    The server provides the ability to set environment
    variables in a flexible way based on characteristics of the client
    request using the directives provided by
    <module>mod_setenvif</module>. Therefore, this directive can be
    used to allow access based on such factors as the clients
    <code>User-Agent</code> (browser type), <code>Referer</code>, or
    other HTTP request header fields.</p>

    <example><title>Example:</title>
      SetEnvIf User-Agent ^KnockKnock/2\.0 let_me_in<br />
      &lt;Directory /docroot&gt;<br />
      <indent>
        Order Deny,Allow<br />
        Deny from all<br />
        Allow from env=let_me_in<br />
      </indent>
      &lt;/Directory&gt;
    </example>

    <p>In this case, browsers with a user-agent string beginning
    with <code>KnockKnock/2.0</code> will be allowed access, and all
    others will be denied.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>Deny</name>
<description>Controls which hosts are denied access to the
server</description>
<syntax> Deny from all|<var>host</var>|env=[!]<var>env-variable</var>
[<var>host</var>|env=[!]<var>env-variable</var>] ...</syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>Limit</override>

<usage>
    <p>This directive allows access to the server to be restricted
    based on hostname, IP address, or environment variables. The
    arguments for the <directive>Deny</directive> directive are
    identical to the arguments for the <directive
    module="mod_access_compat">Allow</directive> directive.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>Order</name>
<description>Controls the default access state and the order in which
<directive>Allow</directive> and <directive>Deny</directive> are
evaluated.</description>
<syntax> Order <var>ordering</var></syntax>
<default>Order Deny,Allow</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>Limit</override>

<usage>

    <p>The <directive>Order</directive> directive, along with the
    <directive module="mod_access_compat">Allow</directive> and
    <directive module="mod_access_compat">Deny</directive> directives,
    controls a three-pass access control system. The first pass
    processes either all <directive
    module="mod_access_compat">Allow</directive> or all <directive
    module="mod_access_compat">Deny</directive> directives, as specified
    by the <directive module="mod_access_compat">Order</directive>
    directive. The second pass parses the rest of the directives
    (<directive module="mod_access_compat">Deny</directive> or
    <directive module="mod_access_compat">Allow</directive>). The third
    pass applies to all requests which do not match either of the first
    two.</p>

    <p>Note that all <directive
    module="mod_access_compat">Allow</directive> and <directive
    module="mod_access_compat">Deny</directive> directives are
    processed, unlike a typical firewall, where only the first match is
    used. The last match is effective (also unlike a typical firewall).
    Additionally, the order in which lines appear in the configuration
    files is not significant -- all <directive
    module="mod_access_compat">Allow</directive> lines are processed as
    one group, all <directive
    module="mod_access_compat">Deny</directive> lines are considered as
    another, and the default state is considered by itself.</p>

    <p><em>Ordering</em> is one of:</p>

    <dl>
      <dt><code>Allow,Deny</code></dt>

      <dd>First, all <directive
      module="mod_access_compat">Allow</directive> directives are
      evaluated; at least one must match, or the request is rejected.
      Next, all <directive module="mod_access_compat">Deny</directive>
      directives are evaluated. If any matches, the request is rejected.
      Last, any requests which do not match an <directive
      module="mod_access_compat">Allow</directive> or a <directive
      module="mod_access_compat">Deny</directive> directive are denied
      by default.</dd>

      <dt><code>Deny,Allow</code></dt>

      <dd>First, all <directive
      module="mod_access_compat">Deny</directive> directives are
      evaluated; if any match, the request is denied
      <strong>unless</strong> it also matches an <directive
      module="mod_access_compat">Allow</directive> directive. Any
      requests which do not match any <directive
      module="mod_access_compat">Allow</directive> or <directive
      module="mod_access_compat">Deny</directive> directives are
      permitted.</dd>

      <dt><code>Mutual-failure</code></dt>

      <dd>This order has the same effect as <code>Order
      Allow,Deny</code> and is deprecated in its favor.</dd>
    </dl>

    <p>Keywords may only be separated by a comma; <em>no whitespace</em>
    is allowed between them.</p>

    <table border="1">
      <tr>
        <th>Match</th>
        <th>Allow,Deny result</th>
        <th>Deny,Allow result</th>
      </tr><tr>
        <th>Match Allow only</th>
        <td>Request allowed</td>
        <td>Request allowed</td>
      </tr><tr>
        <th>Match Deny only</th>
        <td>Request denied</td>
        <td>Request denied</td>
      </tr><tr>
        <th>No match</th>
        <td>Default to second directive: Denied</td>
        <td>Default to second directive: Allowed</td>
      </tr><tr>
        <th>Match both Allow &amp; Deny</th>
        <td>Final match controls: Denied</td>
        <td>Final match controls: Allowed</td>
      </tr>
    </table>

    <p>In the following example, all hosts in the example.org domain
    are allowed access; all other hosts are denied access.</p>

    <example>
      Order Deny,Allow<br />
      Deny from all<br />
      Allow from example.org
    </example>

    <p>In the next example, all hosts in the example.org domain are
    allowed access, except for the hosts which are in the
    foo.example.org subdomain, who are denied access. All hosts not
    in the example.org domain are denied access because the default
    state is to <directive module="mod_access_compat">Deny</directive>
    access to the server.</p>

    <example>
      Order Allow,Deny<br />
      Allow from example.org<br />
      Deny from foo.example.org
    </example>

    <p>On the other hand, if the <directive>Order</directive> in the
    last example is changed to <code>Deny,Allow</code>, all hosts will
    be allowed access. This happens because, regardless of the actual
    ordering of the directives in the configuration file, the
    <code>Allow from example.org</code> will be evaluated last and will
    override the <code>Deny from foo.example.org</code>. All hosts not in
    the <code>example.org</code> domain will also be allowed access
    because the default state is <directive
    module="mod_access_compat">Allow</directive>.</p>

    <p>The presence of an <directive>Order</directive> directive can
    affect access to a part of the server even in the absence of
    accompanying <directive module="mod_access_compat">Allow</directive>
    and <directive module="mod_access_compat">Deny</directive>
    directives because of its effect on the default access state. For
    example,</p>

    <example>
      &lt;Directory /www&gt;<br />
      <indent>
        Order Allow,Deny<br />
      </indent>
      &lt;/Directory&gt;
    </example>

    <p>will Deny all access to the <code>/www</code> directory
    because the default access state is set to
    <directive module="mod_access_compat">Deny</directive>.</p>

    <p>The <directive>Order</directive> directive controls the order of access
    directive processing only within each phase of the server's
    configuration processing. This implies, for example, that an
    <directive module="mod_access_compat">Allow</directive> or <directive
    module="mod_access_compat">Deny</directive> directive occurring in a
    <directive module="core" type="section">Location</directive> section will
    always be evaluated after an <directive
    module="mod_access_compat">Allow</directive> or <directive
    module="mod_access_compat">Deny</directive> directive occurring in a
    <directive module="core" type="section">Directory</directive> section or
    <code>.htaccess</code> file, regardless of the setting of the
    <directive>Order</directive> directive. For details on the merging
    of configuration sections, see the documentation on <a
    href="../sections.html">How Directory, Location and Files sections
    work</a>.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>Satisfy</name>
<description>Interaction between host-level access control and
user authentication</description>
<syntax>Satisfy Any|All</syntax>
<default>Satisfy All</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Influenced by <directive module="core" type="section"
>Limit</directive> and <directive module="core"
type="section">LimitExcept</directive> in version 2.0.51 and
later</compatibility>

<usage>
    <p>Access policy if both <directive
    module="mod_access_compat">Allow</directive> and <directive
    module="mod_authz_core">Require</directive> used. The parameter can be
    either <code>All</code> or <code>Any</code>. This directive is only
    useful if access to a particular area is being restricted by both
    username/password <em>and</em> client host address. In this case
    the default behavior (<code>All</code>) is to require that the client
    passes the address access restriction <em>and</em> enters a valid
    username and password. With the <code>Any</code> option the client will be
    granted access if they either pass the host restriction or enter a
    valid username and password. This can be used to password restrict
    an area, but to let clients from particular addresses in without
    prompting for a password.</p>

    <p>For example, if you wanted to let people on your network have
    unrestricted access to a portion of your website, but require that
    people outside of your network provide a password, you could use a
    configuration similar to the following:</p>

    <example>
      Require valid-user<br />
      Allow from 192.168.1<br />
      Satisfy Any
    </example>

    <p>
    Another frequent use of the <directive>Satisfy</directive> directive
    is to relax access restrictions for a subdirectory:
    </p>

    <example>
      &lt;Directory /var/www/private&gt;<br />
        Require valid-user<br />
      &lt;/Directory&gt;<br />
      <br />
      &lt;Directory /var/www/private/public&gt;<br />
        Allow from all<br />
        Satisfy Any<br />
      &lt;/Directory&gt;
    </example>

    <p>In the above example, authentication will be required for the
    <code>/var/www/private</code> directory, but will not be required
    for the <code>/var/www/private/public</code> directory.</p>

    <p>Since version 2.0.51 <directive>Satisfy</directive> directives can
    be restricted to particular methods by <directive module="core"
    type="section">Limit</directive> and <directive module="core" type="section"
    >LimitExcept</directive> sections.</p>
</usage>
   <seealso><directive module="mod_access_compat">Allow</directive></seealso>
   <seealso><directive module="mod_authz_core">Require</directive></seealso>
</directivesynopsis>

</modulesynopsis>