shorewall_code/manpages/shorewall-policy.xml

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<refentry>
  <refmeta>
    <refentrytitle>shorewall-policy</refentrytitle>

    <manvolnum>5</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>policy</refname>

    <refpurpose>Shorewall policy file</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>/etc/shorewall/policy</command>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>This file defines the high-level policy for connections between
    zones defined in <ulink
    url="shorewall-zones.html">shorewall-zones</ulink>(5).</para>

    <important>
      <para>The order of entries in this file is important</para>

      <para>This file determines what to do with a new connection request if
      we don't get a match from the /etc/shorewall/rules file . For each
      source/destination pair, the file is processed in order until a match is
      found ("all" will match any client or server).</para>
    </important>

    <important>
      <para>Intra-zone policies are pre-defined</para>

      <para>For $FW and for all of the zones defined in /etc/shorewall/zones,
      the POLICY for connections from the zone to itself is ACCEPT (with no
      logging or TCP connection rate limiting) but may be overridden by an
      entry in this file. The overriding entry must be explicit (cannot use
      "all" in the SOURCE or DEST).</para>

      <para>Similarly, if you have IMPLICIT_CONTINUE=Yes in shorewall.conf,
      then the implicit policy to/from any sub-zone is CONTINUE. These
      implicit CONTINUE policies may also be overridden by an explicit entry
      in this file.</para>
    </important>

    <para>The columns in the file are as follows.</para>

    <variablelist>
      <varlistentry>
        <term><emphasis role="bold">SOURCE</emphasis> -
        <emphasis>zone</emphasis>|<emphasis
        role="bold">$FW</emphasis>|<emphasis role="bold">all</emphasis></term>

        <listitem>
          <para>Source zone. Must be the name of a zone defined in <ulink
          url="shorewall-zones.html">shorewall-zones</ulink>(5), $FW or
          "all".</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DEST</emphasis> -
        <emphasis>zone</emphasis>|<emphasis
        role="bold">$FW</emphasis>|<emphasis role="bold">all</emphasis></term>

        <listitem>
          <para>Destination zone. Must be the name of a zone defined in <ulink
          url="shorewall-zones.html">shorewall-zones</ulink>(5), $FW or "all".
          If the DEST is a bport zone, then the SOURCE must be "all", another
          bport zone associated with the same bridge, or it must be an ipv4
          zone that is associated with only the same bridge.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">POLICY</emphasis> - {<emphasis
        role="bold">ACCEPT</emphasis>|<emphasis
        role="bold">DROP</emphasis>|<emphasis
        role="bold">REJECT</emphasis>|<emphasis
        role="bold">CONTINUE</emphasis>|<emphasis
        role="bold">QUEUE</emphasis>|<emphasis
        role="bold">NFQUEUE</emphasis>[(<emphasis>queuenumber</emphasis>)]|<emphasis
        role="bold">NONE</emphasis>}[<emphasis
        role="bold">:</emphasis>{<emphasis>default-action-or-macro</emphasis>|<emphasis
        role="bold">None</emphasis>}]</term>

        <listitem>
          <para>Policy if no match from the rules file is found.</para>

          <para>If the policy is neither CONTINUE nor NONE then the policy may
          be followed by ":" and one of the following:</para>

          <orderedlist numeration="loweralpha">
            <listitem>
              <para>The word "None" or "none". This causes any default action
              defined in <ulink
              url="shorewall.conf.html">shorewall.conf</ulink>(5) to be
              omitted for this policy.</para>
            </listitem>

            <listitem>
              <para>The name of an action (requires that USE_ACTIONS=Yes in
              <ulink url="shorewall.conf.html">shorewall.conf</ulink>(5)).
              That action will be invoked before the policy is
              enforced.</para>
            </listitem>

            <listitem>
              <para>The name of a macro. The rules in that macro will be
              applied before the policy is enforced. This does not require
              USE_ACTIONS=Yes.</para>
            </listitem>
          </orderedlist>

          <blockquote>
            <programlisting></programlisting>

            <para>Possible policies are:</para>
          </blockquote>

          <variablelist>
            <varlistentry>
              <term><emphasis role="bold">ACCEPT</emphasis></term>

              <listitem>
                <para>Accept the connection.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">DROP</emphasis></term>

              <listitem>
                <para>Ignore the connection request.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">REJECT</emphasis></term>

              <listitem>
                <para>For TCP, send RST. For all other, send an "unreachable"
                ICMP.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">QUEUE</emphasis></term>

              <listitem>
                <para>Queue the request for a user-space application such as
                Snort-inline.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">NFQUEUE</emphasis></term>

              <listitem>
                <para>Queue the request for a user-space application using the
                nfnetlink_queue mechanism. If a
                <replaceable>queuenumber</replaceable> is not given, queue
                zero (0) is assumed.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">CONTINUE</emphasis></term>

              <listitem>
                <para>Pass the connection request past any other rules that it
                might also match (where the source or destination zone in
                those rules is a superset of the SOURCE or DEST in this
                policy). See <ulink
                url="shorewall-nesting.html">shorewall-nesting</ulink>(5) for
                additional information.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">NONE</emphasis></term>

              <listitem>
                <para>Assume that there will never be any packets from this
                SOURCE to this DEST. Shorewall will not create any
                infrastructure to handle such packets and you may not have any
                rules with this SOURCE and DEST in the /etc/shorewall/rules
                file. If such a packet <emphasis role="bold">is</emphasis>
                received, the result is undefined. NONE may not be used if the
                SOURCE or DEST columns contain the firewall zone ($FW) or
                "all".</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">LOG LEVEL</emphasis> (Optional) -
        [<emphasis>log-level</emphasis>|<emphasis
        role="bold">ULOG|NFLOG</emphasis>]</term>

        <listitem>
          <para>If supplied, each connection handled under the default POLICY
          is logged at that level. If not supplied, no log message is
          generated. See syslog.conf(5) for a description of log
          levels.</para>

          <para>You may also specify ULOG or NFLOG (must be in upper case).
          This will log to the ULOG or NFLOG target and will send to a
          separate log through use of ulogd (<ulink
          url="http://www.netfilter.org/projects/ulogd/index.html">http://www.netfilter.org/projects/ulogd/index.html</ulink>).</para>

          <para>If you don't want to log but need to specify the following
          column, place "-" here.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">BURST:LIMIT</emphasis> -
        [{<emphasis>s</emphasis>|<emphasis
        role="bold">d</emphasis>}:[[<replaceable>name</replaceable>]:]]]<emphasis>rate</emphasis><emphasis
        role="bold">/</emphasis>{<emphasis
        role="bold">second</emphasis>|<emphasis
        role="bold">minute</emphasis>}[:<emphasis>burst</emphasis>]</term>

        <listitem>
          <para>If passed, specifies the maximum TCP connection
          <emphasis>rate</emphasis> and the size of an acceptable
          <emphasis>burst</emphasis>. If not specified, TCP connections are
          not limited. If the <replaceable>burst</replaceable> parameter is
          omitted, a value of 5 is assumed.</para>

          <para>When <option>s:</option> or <option>d:</option> is specified,
          the rate applies per source IP address or per destination IP address
          respectively. The <replaceable>name</replaceable> may be chosen by
          the user and specifies a hash table to be used to count matching
          connections. If not give, the name <emphasis
          role="bold">shorewall</emphasis> is assumed. Where more than one
          POLICY specifies the same name, the connections counts for the
          policies are aggregated and the individual rates apply to the
          aggregated count.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">CONNLIMIT</emphasis> -
        <emphasis>limit</emphasis>[:<emphasis>mask</emphasis>]</term>

        <listitem>
          <para>May be used to limit the number of simultaneous connections
          from each individual host to <replaceable>limit</replaceable>
          connections. While the limit is only checked on connections to which
          this policy could apply, the number of current connections is
          calculated over all current connections from the SOURCE host. By
          default, the limit is applied to each host individually but can be
          made to apply to networks of hosts by specifying a
          <replaceable>mask</replaceable>. The <replaceable>mask</replaceable>
          specifies the width of a VLSM mask to be applied to the source
          address; the number of current connections is then taken over all
          hosts in the subnet
          <replaceable>source-address</replaceable>/<replaceable>mask</replaceable>.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Example</title>

    <orderedlist numeration="loweralpha">
      <listitem>
        <para>All connections from the local network to the internet are
        allowed</para>
      </listitem>

      <listitem>
        <para>All connections from the internet are ignored but logged at
        syslog level KERNEL.INFO.</para>
      </listitem>

      <listitem>
        <para>All other connection requests are rejected and logged at level
        KERNEL.INFO.</para>
      </listitem>
    </orderedlist>

    <programlisting>        #SOURCE         DEST            POLICY          LOG           BURST:LIMIT
        #                                               LEVEL
        loc             net             ACCEPT
        net             all             DROP            info
        #
        # THE FOLLOWING POLICY MUST BE LAST
        #
        all             all             REJECT          info</programlisting>
  </refsect1>

  <refsect1>
    <title>FILES</title>

    <para>/etc/shorewall/policy</para>
  </refsect1>

  <refsect1>
    <title>See ALSO</title>

    <para>shorewall(8), shorewall-accounting(5), shorewall-actions(5),
    shorewall-blacklist(5), shorewall-hosts(5), shorewall-interfaces(5),
    shorewall-maclist(5), shorewall-masq(5), shorewall-nat(5),
    shorewall-netmap(5), shorewall-params(5), shorewall-policy(5),
    shorewall-providers(5), shorewall-proxyarp(5), shorewall-route_rules(5),
    shorewall-routestopped(5), shorewall-rules(5), shorewall.conf(5),
    shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5),
    shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)</para>
  </refsect1>
</refentry>