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

<name>mod_authz_host</name>
<description>Group authorizations based on host (name or IP
address)</description>
<status>Base</status>
<sourcefile>mod_authz_host.c</sourcefile>
<identifier>authz_host_module</identifier>
<compatibility>The <code>forward-dns</code> provider was addded in 2.4.19</compatibility>

<summary>
    <p>The authorization providers implemented by <module>mod_authz_host</module> are
    registered using the <directive module="mod_authz_core">Require</directive>
    directive. The directive can be referenced within a
    <directive module="core" type="section">Directory</directive>,
    <directive module="core" type="section">Files</directive>,
    or <directive module="core" type="section">Location</directive> section
    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 or IP address.</p>

    <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><a href="../howto/auth.html">Authentication, Authorization,
    and Access Control</a></seealso>
<seealso><directive module="mod_authz_core">Require</directive></seealso>

<section id="requiredirectives"><title>The Require Directives</title>

    <p>Apache's <directive module="mod_authz_core">Require</directive>
    directive is used during the authorization phase to ensure that a user is allowed or
    denied access to a resource.  mod_authz_host extends the
    authorization types with <code>ip</code>, <code>host</code>,
    <code>forward-dns</code> and <code>local</code>.
    Other authorization types may also be
    used but may require that additional authorization modules be loaded.</p>

    <p>These authorization providers affect which hosts can
    access an area of the server. Access can be controlled by
    hostname, IP Address, or IP Address range.</p>

    <p>Since v2.4.8, <a href="../expr.html">expressions</a> are supported
    within the host require directives.</p>

<section id="reqip"><title>Require ip</title>

    <p>The <code>ip</code> provider allows access to the server
    to be controlled based on the IP address of the remote client.
    When <code>Require ip <var>ip-address</var></code> is specified,
    then the request is allowed access if the IP address matches.</p>

    <p>A full IP address:</p>

    <highlight language="config">
Require ip 10.1.2.3
Require ip 192.168.1.104 192.168.1.205
    </highlight>

    <p>An IP address of a host allowed access</p>

    <p>A partial IP address:</p>

    <highlight language="config">
Require ip 10.1
Require ip 10 172.20 192.168.2
    </highlight>
    <p>The first 1 to 3 bytes of an IP address, for subnet
    restriction.</p>

    <p>A network/netmask pair:</p>

    <highlight language="config">
      Require ip 10.1.0.0/255.255.0.0
    </highlight>
    <p>A network a.b.c.d, and a netmask w.x.y.z. For more
    fine-grained subnet restriction.</p>

    <p>A network/nnn CIDR specification:</p>

    <highlight language="config">
      Require ip 10.1.0.0/16
    </highlight>
    <p>Similar to the previous case, except the netmask consists of
    nnn high-order 1 bits.</p>

    <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>

    <highlight language="config">
Require ip 2001:db8::a00:20ff:fea7:ccea
Require ip 2001:db8:1:1::a
Require ip 2001:db8:2:1::/64
Require ip 2001:db8:3::/48
    </highlight>

    <p>Note: As the IP addresses are parsed on startup, expressions are
    not evaluated at request time.</p>

</section>

<section id="reqhost"><title>Require host</title>

    <p>The <code>host</code> provider allows access to the server
    to be controlled based on the host name of the remote client.
    When <code>Require host <var>host-name</var></code> is specified,
    then the request is allowed access if the host name matches.</p>

    <p>A (partial) domain-name</p>

    <highlight language="config">
Require host example.org
Require host .net example.edu
    </highlight>

    <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 to perform a double reverse 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>

</section>

<section id="reqfwddns"><title>Require forward-dns</title>

    <p>The <code>forward-dns</code> provider allows access to the server
    to be controlled based on simple host names.  When
    <code>Require forward-dns <var>host-name</var></code> is specified,
    all IP addresses corresponding to <code><var>host-name</var></code>
    are allowed access.</p>

    <p>In contrast to the <code>host</code> provider, this provider does not
    rely on reverse DNS lookups: it simply queries the DNS for the host name
    and allows a client if its IP matches.  As a consequence, it will only
    work with host names, not domain names.  However, as the reverse DNS is
    not used, it will work with clients which use a dynamic DNS service.</p>

    <highlight language="config">
Require forward-dns bla.example.org
    </highlight>

    <p>A client the IP of which is resolved from the name
    <code>bla.example.org</code> will be granted access.</p>

    <p>The <code>forward-dns</code> provider was added in 2.4.19.</p>
</section>

<section id="reqlocal"><title>Require local</title>

    <p>The <code>local</code> provider allows access to the server if any
    of the following conditions is true:</p>

    <ul>
        <li>the client address matches 127.0.0.0/8</li>
        <li>the client address is ::1</li>
        <li>both the client and the server address of the connection are
        the same</li>
    </ul>

    <p>This allows a convenient way to match connections that originate from
    the local host:</p>

    <highlight language="config">
    Require local
    </highlight>

</section>

<section id="proxy"><title>Security Note</title>

    <p>If you are proxying content to your server, you need to be aware
    that the client address will be the address of your proxy server,
    not the address of the client, and so using the <code>Require</code>
    directive in this context may not do what you mean. See
    <module>mod_remoteip</module> for one possible solution to this
    problem.</p>

</section>

</section>

</modulesynopsis>
