shorewall_code/Shorewall/manpages/shorewall-policy.xml

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

    <manvolnum>5</manvolnum>

    <refmiscinfo>Configuration Files</refmiscinfo>
  </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="/manpages/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 (specifying
      the zone name in both SOURCE and DEST) or it must use "all+" (Shorewall
      4.5.17 or later).</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 (where the column name is
    followed by a different name in parentheses, the different name is used in
    the alternate specification syntax).</para>

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

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

          <para>Support for "all+" was added in Shorewall 4.5.17. "all" does
          not override the implicit intra-zone ACCEPT policy while "all+"
          does.</para>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>Destination zone. Must be the name of a zone defined in <ulink
          url="/manpages/shorewall-zones.html">shorewall-zones</ulink>(5),
          $FW, "all" or "all+". If the DEST is a bport zone, then the SOURCE
          must be "all", "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>

          <para>Support for "all+" was added in Shorewall 4.5.17. "all" does
          not override the implicit intra-zone ACCEPT policy while "all+"
          does.</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>queuenumber1</emphasis>[,<replaceable>queuenumber2</replaceable>])]|<emphasis
        role="bold">NONE</emphasis>}[<emphasis
        role="bold">:</emphasis>{<emphasis>default-action-or-macro</emphasis>[:level]|<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="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5) to
              be omitted for this policy.</para>
            </listitem>

            <listitem>
              <para>The name of an action. The action will be invoked before
              the policy is enforced.</para>
            </listitem>
          </orderedlist>

          <para>Actions can have parameters specified.</para>

          <para>Beginning with Shorewall 4.5.10, the action name can be
          followed optionally by a colon and a log level. The level will be
          applied to each rule in the action or body that does not already
          have a log level.</para>

          <para>Possible actions are:</para>

          <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>queuenumber1</replaceable> is not given, queue
                zero (0) is assumed. Beginning with Shorewall 4.6.10, a second
                queue number (queuenumber2) may be given. This specifies a
                range of queues to use. Packets are then balanced across the
                given queues. This is useful for multicore systems: start
                multiple instances of the userspace program on queues x, x+1,
                .. x+n and use "x:x+n". Packets belonging to the same
                connection are put into the same nfqueue.</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="/manpages/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> (loglevel) -
        [<emphasis>log-level</emphasis>|<emphasis
        role="bold">ULOG|NFLOG</emphasis>]</term>

        <listitem>
          <para>Optional - 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>For a description of log levels, see <ulink
          url="/shorewall_logging.html">http://www.shorewall.net/shorewall_logging.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> (limit) -
        [-|<replaceable>limit</replaceable>]</term>

        <listitem>
          <para>where limit is one of:</para>

          <simplelist>
            <member>[<emphasis
            role="bold">-</emphasis>|[{<emphasis>s</emphasis>|<emphasis
            role="bold">d</emphasis>}:[[<replaceable>name</replaceable>]:]]]<emphasis>rate</emphasis><emphasis
            role="bold">/</emphasis>{<emphasis
            role="bold">sec</emphasis>|<emphasis
            role="bold">min</emphasis>|<emphasis
            role="bold">hour</emphasis>|<emphasis
            role="bold">day</emphasis>}[:<emphasis>burst</emphasis>]</member>

            <member>[<replaceable>name</replaceable>1]:<emphasis>rate1</emphasis><emphasis
            role="bold">/</emphasis>{<emphasis
            role="bold">sec</emphasis>|<emphasis
            role="bold">min</emphasis>|<emphasis
            role="bold">hour</emphasis>|<emphasis
            role="bold">day</emphasis>}[:<emphasis>burst1</emphasis>],[<replaceable>name</replaceable>2]:<emphasis>rate2</emphasis><emphasis
            role="bold">/</emphasis>{<emphasis
            role="bold">sec</emphasis>|<emphasis
            role="bold">min</emphasis>|<emphasis
            role="bold">hour</emphasis>|<emphasis
            role="bold">day</emphasis>}[:<emphasis>burst2</emphasis>]</member>
          </simplelist>

          <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 or rule specifies the same name, the connections counts for
          the policies are aggregated and the individual rates apply to the
          aggregated count.</para>

          <para>Beginning with Shorewall 4.6.5, two<replaceable>
          limit</replaceable>s may be specified, separated by a comma. In this
          case, the first limit (<replaceable>name1</replaceable>,
          <replaceable>rate1</replaceable>, burst1) specifies the per-source
          IP limit and the second limit specifies the per-destination IP
          limit.</para>

          <para>Example: <emphasis
          role="bold">client:10/sec:20,:60/sec:100</emphasis></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><ulink
    url="/configuration_file_basics.htm#Pairs">http://www.shorewall.net/configuration_file_basics.htm#Pairs</ulink></para>

    <para>shorewall(8), shorewall-accounting(5), shorewall-actions(5),
    shorewall-blacklist(5), shorewall-hosts(5), shorewall_interfaces(5),
    shorewall-ipsets(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-rtrules(5), shorewall-routestopped(5), shorewall-rules(5),
    shorewall.conf(5), shorewall-secmarks(5), shorewall-tcclasses(5),
    shorewall-tcdevices(5), shorewall-mangle(5), shorewall-tos(5),
    shorewall-tunnels(5), shorewall-zones(5)</para>
  </refsect1>
</refentry>