shorewall_code/Shorewall/manpages/shorewall-rules.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
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<refentry>
  <refmeta>
    <refentrytitle>shorewall-rules</refentrytitle>

    <manvolnum>5</manvolnum>

    <refmiscinfo>Configuration Files</refmiscinfo>
  </refmeta>

  <refnamediv>
    <refname>rules</refname>

    <refpurpose>Shorewall rules file</refpurpose>
  </refnamediv>

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

  <refsect1>
    <title>Description</title>

    <para>Entries in this file govern connection establishment by defining
    exceptions to the policies laid out in <ulink
    url="/manpages/shorewall-policy.html">shorewall-policy</ulink>(5). By
    default, subsequent requests and responses are automatically allowed using
    connection tracking. For any particular (source,dest) pair of zones, the
    rules are evaluated in the order in which they appear in this file and the
    first terminating match is the one that determines the disposition of the
    request. All rules are terminating except LOG and COUNT rules.</para>

    <warning>
      <para>If you masquerade or use SNAT from a local system to the internet,
      you cannot use an ACCEPT rule to allow traffic from the internet to that
      system. You <emphasis role="bold">must</emphasis> use a DNAT rule
      instead.</para>
    </warning>

    <para>The rules file is divided into sections. Each section is introduced
    by a "Section Header" which is a line beginning with ?SECTION and followed
    by the section name.</para>

    <para>Sections are as follows and must appear in the order listed:</para>

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

        <listitem>
          <para>This section was added in Shorewall 4.4.23. Rules in this
          section are applied, regardless of the connection tracking state of
          the packet.</para>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>Packets in the ESTABLISHED state are processed by rules in
          this section.</para>

          <para>The only ACTIONs allowed in this section are ACCEPT, DROP,
          REJECT, LOG, NFQUEUE and QUEUE</para>

          <para>There is an implicit ACCEPT rule inserted at the end of this
          section.</para>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>Packets in the RELATED state are processed by rules in this
          section.</para>

          <para>The only ACTIONs allowed in this section are ACCEPT, DROP,
          REJECT, LOG, NFQUEUE and QUEUE</para>

          <para>There is an implicit rule added at the end of this section
          that invokes the RELATED_DISPOSITION (<ulink
          url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5)).</para>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>Added in Shorewall 4.5.13. Packets in the INVALID state are
          processed by rules in this section.</para>

          <para>The only Actions allowed in this section are ACCEPT, DROP,
          REJECT, LOG, NFQUEUE and QUEUE.</para>

          <para>There is an implicit rule added at the end of this section
          that invokes the INVALID_DISPOSITION (<ulink
          url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5)).</para>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>Added in Shorewall 4.5.13. Packets in the UNTRACKED state are
          processed by rules in this section.</para>

          <para>The only Actions allowed in this section are ACCEPT, DROP,
          REJECT, LOG, NFQUEUE and QUEUE.</para>

          <para>There is an implicit rule added at the end of this section
          that invokes the UNTRACKED_DISPOSITION (<ulink
          url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5)).</para>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>Packets in the NEW state are processed by rules in this
          section. If the INVALID and/or UNTRACKED sections are empty or not
          included, then the packets in the corresponding state(s) are also
          processed in this section.</para>
        </listitem>
      </varlistentry>
    </variablelist>

    <note>
      <para>If you are not familiar with Netfilter to the point where you are
      comfortable with the differences between the various connection tracking
      states, then it is suggested that you omit the <emphasis
      role="bold">ESTABLISHED</emphasis> and <emphasis
      role="bold">RELATED</emphasis> sections and place all of your rules in
      the NEW section (That's after the line that reads ?SECTION NEW').</para>
    </note>

    <warning>
      <para>If you specify FASTACCEPT=Yes in <ulink
      url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5) then the
      <emphasis role="bold">ALL, ESTABLISHED</emphasis> and <emphasis
      role="bold">RELATED</emphasis> sections must be empty.</para>

      <para>An except is made if you are running Shorewall 4.4.27 or later and
      you have specified a non-default value for RELATED_DISPOSITION or
      RELATED_LOG_LEVEL. In that case, you may have rules in the RELATED
      section of this file.</para>
    </warning>

    <para>You may omit any section that you don't need. If no Section Headers
    appear in the file then all rules are assumed to be in the NEW
    section.</para>

    <para>When defining rules that rewrite the destination IP address and/or
    port number (namely DNAT and REDIRECT rules), it is important to keep
    straight which columns in the file specify the packet before rewriting and
    which specify how the packet will look after rewriting.</para>

    <itemizedlist>
      <listitem>
        <para>The DEST column specifies the final destination for the packet
        after rewriting and can include the final IP address and/or port
        number.</para>
      </listitem>

      <listitem>
        <para>The remaining columns specify characteristics of the packet
        before rewriting. In particular, the ORIGDEST column gives the
        original destination IP address of the packet and the DPORT column
        give the original destination port(s).</para>
      </listitem>
    </itemizedlist>

    <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">ACTION</emphasis> - <emphasis
        role="bold"><replaceable>target</replaceable>[:</emphasis>{<emphasis>log-level</emphasis>|<emphasis
        role="bold">none</emphasis>}[<emphasis role="bold"><emphasis
        role="bold">!</emphasis></emphasis>][<emphasis
        role="bold">:</emphasis><emphasis>tag</emphasis>]]</term>

        <listitem>
          <para>Specifies the action to be taken if the connection request
          matches the rule. <replaceable>target</replaceable> must be one of
          the following.</para>

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

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

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

              <listitem>
                <para>like ACCEPT but also excludes the connection from any
                subsequent matching <emphasis
                role="bold">DNAT</emphasis>[<emphasis
                role="bold">-</emphasis>] or <emphasis
                role="bold">REDIRECT</emphasis>[<emphasis
                role="bold">-</emphasis>] rules.</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>like ACCEPT but exempts the rule from being suppressed
                by OPTIMIZE=1 in <ulink
                url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis>action</emphasis></term>

              <listitem>
                <para>The name of an <emphasis>action</emphasis> declared in
                <ulink
                url="/manpages/shorewall-actions.html">shorewall-actions</ulink>(5)
                or in /usr/share/shorewall/actions.std.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">ADD(<replaceable>ipset</replaceable>:<replaceable>flags</replaceable>[:<replaceable>timeout</replaceable>])</emphasis></term>

              <listitem>
                <para>Added in Shorewall 4.4.12. Causes addresses and/or port
                numbers to be added to the named
                <replaceable>ipset</replaceable>. The
                <replaceable>flags</replaceable> specify the address or tuple
                to be added to the set and must match the type of ipset
                involved. For example, for an iphash ipset, either the SOURCE
                or DESTINATION address can be added using
                <replaceable>flags</replaceable> <emphasis
                role="bold">src</emphasis> or <emphasis
                role="bold">dst</emphasis> respectively (see the -A command in
                ipset (8)).</para>

                <para>Beginning with Shorewall 5.0.3, an optional
                <replaceable>timeout</replaceable> can be specified. This is
                the number of seconds that the new entry in the ipset is to
                remain valid and overrides any timeout specified when the
                ipset was created.</para>

                <para>ADD is non-terminating. Even if a packet matches the
                rule, it is passed on to the next rule.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">AUDIT</emphasis>[(accept|drop|reject)]</term>

              <listitem>
                <para>Added in Shorewall 4.5.10. Audits the packet with the
                specified type; if the type is omitted, then
                <option>drop</option> is assumed. Require AUDIT_TARGET support
                in the kernel and iptables.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">A_ACCEPT</emphasis>, <emphasis
              role="bold">A_ACCEPT</emphasis><emphasis
              role="bold">+</emphasis> and <emphasis
              role="bold">A_ACCEPT</emphasis><emphasis
              role="bold">!</emphasis></term>

              <listitem>
                <para>Added in Shorewall 4.4.20. Audited versions of ACCEPT,
                ACCEPT+ and ACCEPT! respectively. Require AUDIT_TARGET support
                in the kernel and iptables.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">A_DROP</emphasis> and<emphasis
              role="bold"> A_DROP!</emphasis></term>

              <listitem>
                <para>Added in Shorewall 4.4.20. Audited versions of DROP and
                DROP! respectively. Require AUDIT_TARGET support in the kernel
                and iptables.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">A_REJECT</emphasis> AND <emphasis
              role="bold">A_REJECT!</emphasis></term>

              <listitem>
                <para>Added in Shorewall 4.4.20. Audited versions of REJECT
                and REJECT! respectively. Require AUDIT_TARGET support in the
                kernel and iptables.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">?COMMENT</emphasis></term>

              <listitem>
                <para>the rest of the line will be attached as a comment to
                the Netfilter rule(s) generated by the following entries. The
                comment will appear delimited by "/* ... */" in the output of
                "shorewall show &lt;chain&gt;". To stop the comment from being
                attached to further rules, simply include ?COMMENT on a line
                by itself.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">CONMARK({<replaceable>mark</replaceable>})</emphasis></term>

              <listitem>
                <para>Added in Shorewall 5.0.7, CONNMARK is identical to MARK
                with the exception that the mark is assigned to connection to
                which the packet belongs is marked rather than to the packet
                itself.</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>For experts only.</para>

                <para>Do not process any of the following rules for this
                (source zone,destination zone). If the source and/or
                destination IP address falls into a zone defined later in
                <ulink
                url="/manpages/shorewall-zones.html">shorewall-zones</ulink>(5)
                or in a parent zone of the source or destination zones, then
                this connection request will be passed to the rules defined
                for that (those) zone(s). See <ulink
                url="/manpages/shorewall-nesting.html">shorewall-nesting</ulink>(5)
                for additional information.</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>like CONTINUE but exempts the rule from being suppressed
                by OPTIMIZE=1 in <ulink
                url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5).</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>Simply increment the rule's packet and byte count and
                pass the packet to the next rule.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">DEL(<replaceable>ipset</replaceable>:<replaceable>flags</replaceable>)</emphasis></term>

              <listitem>
                <para>Added in Shorewall 4.4.12. Causes an entry to be deleted
                from the named <replaceable>ipset</replaceable>. The
                <replaceable>flags</replaceable> specify the address or tuple
                to be deleted from the set and must match the type of ipset
                involved. For example, for an iphash ipset, either the SOURCE
                or DESTINATION address can be deleted using
                <replaceable>flags</replaceable> <emphasis
                role="bold">src</emphasis> or <emphasis
                role="bold">dst</emphasis> respectively (see the -D command in
                ipset (8)).</para>

                <para>DEL is non-terminating. Even if a packet matches the
                rule, it is passed on to the next rule.</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>Forward the request to another system (and optionally
                another port).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">DNAT-</emphasis></term>

              <listitem>
                <para>Advanced users only.</para>

                <para>Like <emphasis role="bold">DNAT</emphasis> but only
                generates the <emphasis role="bold">DNAT</emphasis> iptables
                rule and not the companion <emphasis
                role="bold">ACCEPT</emphasis> rule.</para>
              </listitem>
            </varlistentry>

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

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

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

              <listitem>
                <para>like DROP but exempts the rule from being suppressed by
                OPTIMIZE=1 in <ulink
                url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5).</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>Added in Shorewall 4.5.7. This action requires that the
                HELPER column contains the name of the Netfilter helper to be
                associated with connections matching this connection. May only
                be specified in the NEW section and is useful for being able
                to specify a helper when the applicable policy is ACCEPT. No
                destination zone should be specified in HELPER rules.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">INLINE</emphasis>[(<replaceable>action</replaceable>)]</term>

              <listitem>
                <para>Added in Shorewall 4.5.16. This action allows you to
                construct most of the rule yourself using iptables syntax. The
                part that you specify must follow a semicolon (';') and is
                completely free-form. If the target of the rule (the part
                following 'j') is something that Shorewall supports in the
                ACTION column, then you may enclose it in parentheses (e.g.,
                INLINE(ACCEPT)). Otherwise, you can include it after the
                semicolon. In this case, you must declare the target as a
                builtin action in <ulink
                url="/manpages/shorewall-actions.html">shorewall-actions</ulink>(5).</para>

                <para>Some considerations when using INLINE:</para>

                <itemizedlist>
                  <listitem>
                    <para>The <option>p</option>, <option>s</option>,
                    <option>d</option>, <option>i</option>,
                    <option>o</option>, <option>policy</option>, and state
                    match (<option>state</option> or <option>conntrack
                    --ctstate</option>) matches will always appear in the
                    front of the rule in that order.</para>
                  </listitem>

                  <listitem>
                    <para>When multiple matches are specified, the compiler
                    will keep them in the order in which they appear
                    (excluding the above listed ones), but they will not
                    necessarily be at the end of the generated rule. For
                    example, if addresses are specified in the SOURCE and/or
                    DEST columns, their generated matches will appear after
                    those specified using ';'.</para>
                  </listitem>
                </itemizedlist>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">IPTABLES</emphasis>({<replaceable>iptables-target</replaceable>
              [<replaceable>option</replaceable> ...])</term>

              <listitem>
                <para>This action allows you to specify an iptables target
                with options (e.g., 'IPTABLES(MARK --set-xmark 0x01/0xff)'. If
                the <replaceable>iptables-target</replaceable> is not one
                recognized by Shorewall, the following error message will be
                issued:</para>

                <programlisting>    ERROR: Unknown target (<replaceable>iptables-target</replaceable>)</programlisting>

                <para>This error message may be eliminated by adding the
                <replaceable>iptables-</replaceable><replaceable>target</replaceable>
                as a builtin action in <ulink
                url="/manpages/shorewall-actions.html">shorewall-actions</ulink>(5).</para>

                <important>
                  <para>If you specify REJECT as the
                  <replaceable>iptables-target</replaceable>, the target of
                  the rule will be the iptables REJECT target and not
                  Shorewall's builtin 'reject' chain which is used when REJECT
                  (see below) is specified as the
                  <replaceable>target</replaceable> in the ACTION
                  column.</para>
                </important>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">LOG:<replaceable>level</replaceable></emphasis></term>

              <listitem>
                <para>Simply log the packet and continue with the next
                rule.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis>macro</emphasis><emphasis
              role="bold">[(<replaceable>macrotarget</replaceable>)]</emphasis></term>

              <listitem>
                <para>The name of a macro defined in a file named
                macro.<emphasis>macro</emphasis>. If the macro accepts an
                action parameter (Look at the macro source to see if it has
                PARAM in the TARGET column) then the
                <emphasis>macro</emphasis> name is followed by the
                parenthesized <emphasis>macrotarget</emphasis> (<emphasis
                role="bold">ACCEPT</emphasis>, <emphasis
                role="bold">DROP</emphasis>, <emphasis
                role="bold">REJECT</emphasis>, ...) to be substituted for the
                parameter.</para>

                <para>Example: FTP(ACCEPT).</para>

                <para>The older syntax where the macro name and the target are
                separated by a slash (e.g. FTP/ACCEPT) is still allowed but is
                deprecated.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">MARK({<replaceable>mark</replaceable>})</emphasis></term>

              <listitem>
                <para>where <replaceable>mark</replaceable> is a packet mark
                value.</para>

                <para>Added in Shorewall 5.0.7, MARK requires "Mark in filter
                table" support in your kernel and iptables.</para>

                <para>Normally will set the mark value of the current packet.
                If preceded by a vertical bar ("|"), the mark value will be
                logically ORed with the current mark value to produce a new
                mark value. If preceded by an ampersand ("&amp;"), will be
                logically ANDed with the current mark value to produce a new
                mark value.</para>

                <para>Both "|" and "&amp;" require Extended MARK Target
                support in your kernel and iptables.</para>

                <para>The mark value may be optionally followed by "/" and a
                mask value (used to determine those bits of the connection
                mark to actually be set). When a mask is specified, the result
                of logically ANDing the mark value with the mask must be the
                same as the mark value.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">NFLOG</emphasis>[(<replaceable>nflog-parameters</replaceable>)]</term>

              <listitem>
                <para>Added in Shorewall 4.5.9.3. Queues matching packets to a
                back end logging daemon via a netlink socket then continues to
                the next rule. See <ulink
                url="/shorewall.logging.html">http://www.shorewall.net/shorewall_logging.html</ulink>.</para>

                <para>The <replaceable>nflog-parameters</replaceable> are a
                comma-separated list of up to 3 numbers:</para>

                <itemizedlist>
                  <listitem>
                    <para>The first number specifies the netlink group
                    (0-65535). If omitted (e.g., NFLOG(,0,10)) then a value of
                    0 is assumed.</para>
                  </listitem>

                  <listitem>
                    <para>The second number specifies the maximum number of
                    bytes to copy. If omitted, 0 (no limit) is assumed.</para>
                  </listitem>

                  <listitem>
                    <para>The third number specifies the number of log
                    messages that should be buffered in the kernel before they
                    are sent to user space. The default is 1.</para>
                  </listitem>
                </itemizedlist>

                <para>NFLOG is similar to<emphasis role="bold">
                LOG:NFLOG</emphasis>[(<replaceable>nflog-parameters</replaceable>)],
                except that the log level is not changed when this ACTION is
                used in an action or macro body and the invocation of that
                action or macro specifies a log level.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">NFQUEUE</emphasis>[([<replaceable>queuenumber</replaceable>1[:<replaceable>queuenumber2</replaceable>[c]][,bypass]]|bypass)]</term>

              <listitem>
                <para>Queues the packet to a user-space application using the
                nfnetlink_queue mechanism. If a
                <replaceable>queuenumber</replaceable>1 is not specified,
                queue zero (0) is assumed. Beginning with Shorewall 4.6.10,
                the keyword <emphasis role="bold">bypass</emphasis> can be
                given. By default, if no userspace program is listening on an
                NFQUEUE, then all packets that are to be queued are dropped.
                When this option is used, the NFQUEUE rule is silently
                bypassed instead. The packet will move on to the next rule.
                Also beginning in Shorewall 4.6.10, a second queue number
                (<replaceable>queuenumber2</replaceable>) may be specified.
                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>

                <para>Beginning with Shorewall 5.1.0, queuenumber2 may be
                followed by the letter 'c' to indicate that the CPU ID will be
                used as an index to map packets to the queues. The idea is
                that you can improve performance if there's a queue per CPU.
                Requires the NFQUEUE CPU Fanout capability in your kernel and
                iptables.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold"><emphasis
              role="bold">NFQUEUE!</emphasis>[([<replaceable>queuenumber1</replaceable>[:<replaceable>queuenumber2</replaceable>[c]][,bypass]]|bypass)]</emphasis></term>

              <listitem>
                <para>like NFQUEUE but exempts the rule from being suppressed
                by OPTIMIZE=1 in <ulink
                url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5).</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>Excludes the connection from any subsequent <emphasis
                role="bold">DNAT</emphasis>[-] or <emphasis
                role="bold">REDIRECT</emphasis>[-] rules but doesn't generate
                a rule to accept the traffic.</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>Queue the packet to a user-space application such as
                ftwall (http://p2pwall.sf.net). The application may reinsert
                the packet for further processing.</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>like QUEUE but exempts the rule from being suppressed by
                OPTIMIZE=1 in <ulink
                url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">REJECT[(<replaceable>option</replaceable>)]</emphasis></term>

              <listitem>
                <para>disallow the request and return an icmp-unreachable or
                an RST packet. If no option is passed, Shorewall selects the
                appropriate option based on the protocol of the packet.</para>

                <para>Beginning with Shorewall 5.0.8, the type of reject may
                be specified in the <replaceable>option</replaceable>
                paramater. Valid <replaceable>option</replaceable> values
                are:</para>

                <simplelist>
                  <member><option>icmp-net-unreachable</option></member>

                  <member><option>icmp-host-unreachable</option></member>

                  <member><option>i</option><option>cmp-port-unreachable</option></member>

                  <member><option>icmp-proto-unreachable</option></member>

                  <member><option>icmp-net-prohibited</option></member>

                  <member><option>icmp-host-prohibited</option></member>

                  <member><option>icmp-admin-prohibited</option></member>

                  <member><option>icmp-tcp-reset</option> (the PROTO column
                  must specify TCP). Beginning with Shorewall 5.1.3, this
                  option may also be specified as
                  <option>tcp-reset</option>.</member>
                </simplelist>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>like REJECT but exempts the rule from being suppressed
                by OPTIMIZE=1 in <ulink
                url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5).</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>Redirect the request to a server running on the
                firewall.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">REDIRECT-</emphasis></term>

              <listitem>
                <para>Advanced users only.</para>

                <para>Like <emphasis role="bold">REDIRECT</emphasis> but only
                generates the <emphasis role="bold">REDIRECT</emphasis>
                iptables rule and not the companion <emphasis
                role="bold">ACCEPT</emphasis> rule.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">TARPIT</emphasis> [(<emphasis
              role="bold">tarpit</emphasis> | <emphasis
              role="bold">honeypot</emphasis> | <emphasis
              role="bold">reset</emphasis>)]</term>

              <listitem>
                <para>Added in Shorewall 4.6.6.</para>

                <para>TARPIT captures and holds incoming TCP connections using
                no local per-connection resources.</para>

                <para>TARPIT only works with the PROTO column set to tcp (6),
                and is totally application agnostic. This module will answer a
                TCP request and play along like a listening server, but aside
                from sending an ACK or RST, no data is sent. Incoming packets
                are ignored and dropped. The attacker will terminate the
                session eventually. This module allows the initial packets of
                an attack to be captured by other software for inspection. In
                most cases this is sufficient to determine the nature of the
                attack.</para>

                <para>This offers similar functionality to LaBrea
                &lt;http://www.hackbusters.net/LaBrea/&gt; but does not
                require dedicated hardware or IPs. Any TCP port that you would
                normally DROP or REJECT can instead become a tarpit.</para>

                <para>The target accepts a single optional parameter:</para>

                <variablelist>
                  <varlistentry>
                    <term>tarpit</term>

                    <listitem>
                      <para>This mode is the default and completes a
                      connection with the attacker but limits the window size
                      to 0, thus keeping the attacker waiting long periods of
                      time. While he is maintaining state of the connection
                      and trying to continue every 60-240 seconds, we keep
                      none, so it is very lightweight. Attempts to close the
                      connection are ignored, forcing the remote side to time
                      out the connection in 12-24 minutes.</para>
                    </listitem>
                  </varlistentry>

                  <varlistentry>
                    <term>honeypot</term>

                    <listitem>
                      <para>This mode completes a connection with the
                      attacker, but signals a normal window size, so that the
                      remote side will attempt to send data, often with some
                      very nasty exploit attempts. We can capture these
                      packets for decoding and further analysis. The module
                      does not send any data, so if the remote expects an
                      application level response, the game is up.</para>
                    </listitem>
                  </varlistentry>

                  <varlistentry>
                    <term>reset</term>

                    <listitem>
                      <para>This mode is handy because we can send an inline
                      RST (reset). It has no other function.</para>
                    </listitem>
                  </varlistentry>
                </variablelist>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">ULOG</emphasis>[(<replaceable>ulog-parameters</replaceable>)]</term>

              <listitem>
                <para>Added in Shorewall 4.5.10. Queues matching packets to a
                back end logging daemon via a netlink socket then continues to
                the next rule. See <ulink
                url="/shorewall.logging.html">http://www.shorewall.net/shorewall_logging.html</ulink>.</para>

                <para>Similar to<emphasis role="bold">
                LOG:ULOG</emphasis>[(<replaceable>ulog-parameters</replaceable>)],
                except that the log level is not changed when this ACTION is
                used in an action or macro body and the invocation of that
                action or macro specifies a log level.</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>The <replaceable>target</replaceable> may optionally be
          followed by ":" and a syslog log level (e.g, REJECT:info or
          Web(ACCEPT):debug). This causes the packet to be logged at the
          specified level. Note that if the <emphasis
          role="bold">ACTION</emphasis> involves destination network address
          translation (DNAT, REDIRECT, etc.) then the packet is logged
          <emphasis role="bold">before</emphasis> the destination address is
          rewritten.</para>

          <para>If the <emphasis role="bold">ACTION</emphasis> names an
          <emphasis>action</emphasis> declared in <ulink
          url="/manpages/shorewall-actions.html">shorewall-actions</ulink>(5)
          or in /usr/share/shorewall/actions.std then:</para>

          <itemizedlist>
            <listitem>
              <para>If the log level is followed by "!' then all rules in the
              action are logged at the log level.</para>
            </listitem>

            <listitem>
              <para>If the log level is not followed by "!" then only those
              rules in the action that do not specify logging are logged at
              the specified level.</para>
            </listitem>

            <listitem>
              <para>The special log level <emphasis
              role="bold">none!</emphasis> suppresses logging by the
              action.</para>
            </listitem>
          </itemizedlist>

          <para>You may also specify <emphasis role="bold">ULOG</emphasis> or
          <emphasis role="bold">NFLOG</emphasis> (must be in upper case) as a
          log level.This will log to the ULOG or NFLOG target for routing 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>Actions specifying logging may be followed by a log tag (a
          string of alphanumeric characters) which is appended to the string
          generated by the LOGPREFIX (in <ulink
          url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5)).</para>

          <para>Example: ACCEPT:info:ftp would include 'ftp ' at the end of
          the log prefix generated by the LOGPREFIX setting.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">SOURCE -
        <replaceable>source-spec</replaceable>[,...]</emphasis></term>

        <listitem>
          <para>Source hosts to which the rule applies.</para>

          <para><replaceable>source-spec</replaceable> is one of the
          following:</para>

          <variablelist>
            <varlistentry>
              <term><emphasis
              role="bold"><replaceable>zone</replaceable>[,...[+]]</emphasis></term>

              <listitem>
                <para>The name of a zone defined in <ulink
                url="shorewall-zones.html">shorewall-zones</ulink>(5). When
                only the zone name is specified, the packet source may be any
                host in that zone.</para>

                <para>zone may also be one of the following:</para>

                <variablelist>
                  <varlistentry>
                    <term>all[+][-]</term>

                    <listitem>
                      <para><emphasis role="bold">all</emphasis>, without the
                      "-" means "All Zones, including the firewall zone". If
                      the "-" is included, the firewall zone is omitted.
                      Normally all omits intra-zone traffic, but intra-zone
                      traffic can be included specifying "+".</para>
                    </listitem>
                  </varlistentry>

                  <varlistentry>
                    <term>any[+][-]</term>

                    <listitem>
                      <para><emphasis role="bold">any</emphasis> is equivalent
                      to <emphasis role="bold">all</emphasis> when there are
                      no nested zones. When there are nested zones, <emphasis
                      role="bold">any</emphasis> only refers to top-level
                      zones (those with no parent zones). Note that <emphasis
                      role="bold">any</emphasis> excludes all vserver zones,
                      since those zones are nested within the firewall
                      zone.</para>
                    </listitem>
                  </varlistentry>

                  <varlistentry>
                    <term>none</term>

                    <listitem>
                      <para>When <emphasis role="bold">none</emphasis> is used
                      either in the <emphasis role="bold">SOURCE</emphasis> or
                      <emphasis role="bold">DEST</emphasis> column, the rule
                      is ignored.</para>
                    </listitem>
                  </varlistentry>
                </variablelist>

                <para>Similar to with <emphasis role="bold">all</emphasis> and
                <emphasis role="bold">any</emphasis>, intra-zone traffic is
                normally excluded when multiple zones are listed. Intra-zone
                traffic may be included by following the list with a plus sign
                ("+").</para>

                <para><emphasis role="bold">all</emphasis> and <emphasis
                role="bold">any</emphasis> may be followed by an exclamation
                point ("!") and a comma-separated list of zone names to be
                omitted.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>interface</replaceable></term>

              <listitem>
                <para>When this form is used,
                <replaceable>interface</replaceable> must be the name of an
                interface associated with the named
                <replaceable>zone</replaceable> in either <ulink
                url="shorewall-interfaces.html">shorewall-interfaces</ulink>(5)
                or <ulink
                url="shorewall.hosts.html">shorewall-hosts</ulink>(5). Only
                packets from hosts in the <replaceable>zone</replaceable> that
                arrive through the named interface will match the rule.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>address</replaceable>[,...]</term>

              <listitem>
                <para>where address can be:</para>

                <itemizedlist>
                  <listitem>
                    <para>A host or network IP address. A network address may
                    be followed by exclusion (see <ulink
                    url="shorewall-exclusion.html">shorewall-exclusion</ulink>(5)).</para>
                  </listitem>

                  <listitem>
                    <para>An address range, specified using the syntax
                    <emphasis>lowaddress</emphasis>-<emphasis>highaddress</emphasis>.</para>
                  </listitem>

                  <listitem>
                    <para>+<replaceable>ipset</replaceable> where
                    <replaceable>ipset</replaceable> is the name of an ipset
                    and must be preceded by a plus sign ("+").</para>
                  </listitem>

                  <listitem>
                    <para>A MAC address in Shorewall format (preceded by a
                    tilde ("~") and with the hex byte values separated by
                    dashes (e.g., "~00-0a-f6-04-9c-7d").</para>
                  </listitem>

                  <listitem>
                    <para>^<replaceable>country-code</replaceable> where
                    country-code is a two-character ISO-3661 country code
                    preceded by a caret ("^").</para>
                  </listitem>

                  <listitem>
                    <para>^<replaceable>country-code-list</replaceable> where
                    <replaceable>country-code-list</replaceable> is a
                    comma-separated list of up to 15 ISO-3661 country codes
                    enclosed in square brackets ("[...]").</para>
                  </listitem>

                  <listitem>
                    <para>The primary IP address of a firewall interface can
                    be specified by an ampersand ('&amp;') followed by the
                    logical name of the interface as found in the INTERFACE
                    column of <ulink
                    url="/manpages/shorewall-interfaces.html">shorewall-interfaces</ulink>
                    (5).</para>
                  </listitem>
                </itemizedlist>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>interface</replaceable>:<replaceable>address</replaceable>[,...]</term>

              <listitem>
                <para>This form combines the preceding two and requires that
                both the incoming interface and source address match.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>exclusion</replaceable></term>

              <listitem>
                <para>This form matches if the host IP address does not match
                any of the entries in the exclusion (see <ulink
                url="shorewall-exclusion.html">shorewall-exclusion</ulink>(5)).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>interface</replaceable>:<replaceable>exclusion</replaceable></term>

              <listitem>
                <para>This form matches packets from the named
                <replaceable>zone</replaceable> entering through the specified
                <replaceable>interface</replaceable> where the source address
                does not match any entry in the
                <replaceable>exclusion</replaceable>.</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>Beginning with Shorewall 5.1.0, multiple
          <replaceable>source-spec</replaceable>s may be listed, provided that
          extended forms of the source-spec are used:</para>

          <blockquote>
            <para><replaceable>zone</replaceable>:(<replaceable>interface</replaceable>)</para>

            <para><replaceable>zone</replaceable>:(<replaceable>address</replaceable>[,...])</para>

            <para>zone:(interface:address[,...])</para>

            <para><replaceable>zone</replaceable>:(<replaceable>exclusion</replaceable>)</para>

            <para><replaceable>zone</replaceable>:(<replaceable>interface</replaceable>:<replaceable>exclusion</replaceable>)</para>
          </blockquote>

          <para>Examples:</para>

          <variablelist>
            <varlistentry>
              <term>dmz:192.168.2.2</term>

              <listitem>
                <para>Host 192.168.2.2 in the DMZ</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:155.186.235.0/24</term>

              <listitem>
                <para>Subnet 155.186.235.0/24 on the Internet</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>loc:192.168.1.1,192.168.1.2</term>

              <listitem>
                <para>Hosts 192.168.1.1 and 192.168.1.2 in the local
                zone.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>loc:~00-A0-C9-15-39-78</term>

              <listitem>
                <para>Host in the local zone with MAC address
                00:A0:C9:15:39:78.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:192.0.2.11-192.0.2.17</term>

              <listitem>
                <para>Hosts 192.0.2.11-192.0.2.17 in the net zone.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:!192.0.2.11-192.0.2.17</term>

              <listitem>
                <para>All hosts in the net zone except for
                192.0.2.11-192.0.2.17.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:155.186.235.0/24!155.186.235.16/28</term>

              <listitem>
                <para>Subnet 155.186.235.0/24 on the Internet except for
                155.186.235.16/28</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>$FW:&amp;eth0</term>

              <listitem>
                <para>The primary IP address of eth0 in the firewall
                zone.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>loc,dmz</term>

              <listitem>
                <para>Both the <emphasis role="bold">loc</emphasis> and
                <emphasis role="bold">dmz</emphasis> zones.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>all!dmz</term>

              <listitem>
                <para>All but the <emphasis role="bold">dmz</emphasis>
                zone.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:^CN</term>

              <listitem>
                <para>China.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>loc:(eth1:1.2.3.4,2.3.4.5),dmz:(eth2:5.6.7.8,9.10.11.12),net</term>

              <listitem>
                <para>Hosts 1.2.3.4 and 2.3.4.5 in the loc zone when the
                packet arrives through eth1 plus hosts 5.6.7.8 and 9.10.11.12
                in the dmz zone when the packet arrives through eth2 plus all
                of the net zone.</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DEST -
        <replaceable>dest-spec</replaceable>[,...]</emphasis></term>

        <listitem>
          <para>Destination hosts to which the rule applies.</para>

          <para><replaceable>dest-spec</replaceable> is one of the
          following:</para>

          <variablelist>
            <varlistentry>
              <term><emphasis
              role="bold"><replaceable>zone</replaceable>[,...[+]]</emphasis></term>

              <listitem>
                <para>The name of a zone defined in <ulink
                url="shorewall-zones.html">shorewall-zones</ulink>(5). When
                only the zone name is specified, the packet destination may be
                any host in that zone.</para>

                <para>zone may also be one of the following:</para>

                <variablelist>
                  <varlistentry>
                    <term>all[+][-]</term>

                    <listitem>
                      <para><emphasis role="bold">all</emphasis>, without the
                      "-" means "All Zones, including the firewall zone". If
                      the "-" is included, the firewall zone is omitted.
                      Normally all omits intra-zone traffic, but intra-zone
                      traffic can be included specifying "+".</para>
                    </listitem>
                  </varlistentry>

                  <varlistentry>
                    <term>any[+][-]</term>

                    <listitem>
                      <para><emphasis role="bold">any</emphasis> is equivalent
                      to <emphasis role="bold">all</emphasis> when there are
                      no nested zones. When there are nested zones, <emphasis
                      role="bold">any</emphasis> only refers to top-level
                      zones (those with no parent zones). Note that <emphasis
                      role="bold">any</emphasis> excludes all vserver zones,
                      since those zones are nested within the firewall
                      zone.</para>
                    </listitem>
                  </varlistentry>

                  <varlistentry>
                    <term>none</term>

                    <listitem>
                      <para>When <emphasis role="bold">none</emphasis> is used
                      either in the <emphasis role="bold">SOURCE</emphasis> or
                      <emphasis role="bold">DEST</emphasis> column, the rule
                      is ignored.</para>
                    </listitem>
                  </varlistentry>
                </variablelist>

                <para>Similar to with <emphasis role="bold">all</emphasis> and
                <emphasis role="bold">any</emphasis>, intra-zone traffic is
                normally excluded when multiple zones are listed. Intra-zone
                traffic may be included by following the list with a plus sign
                ("+").</para>

                <para><emphasis role="bold">all</emphasis> and <emphasis
                role="bold">any</emphasis> may be followed by an exclamation
                point ("!") and a comma-separated list of zone names to be
                omitted.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>interface</replaceable></term>

              <listitem>
                <para>When this form is used,
                <replaceable>interface</replaceable> must be the name of an
                interface associated with the named
                <replaceable>zone</replaceable> in either <ulink
                url="shorewall-interfaces.html">shorewall-interfaces</ulink>(5)
                or <ulink
                url="shorewall.hosts.html">shorewall-hosts</ulink>(5). Only
                packets to hosts in the <replaceable>zone</replaceable> that
                are sent through the named interface will match the
                rule.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>address</replaceable>[,...]</term>

              <listitem>
                <para>where address can be:</para>

                <itemizedlist>
                  <listitem>
                    <para>A host or network IP address. A network address may
                    be followed by exclusion (see <ulink
                    url="shorewall-exclusion.html">shorewall-exclusion</ulink>(5)).</para>
                  </listitem>

                  <listitem>
                    <para>An address range, specified using the syntax
                    <emphasis>lowaddress</emphasis>-<emphasis>highaddress</emphasis>.</para>
                  </listitem>

                  <listitem>
                    <para>+<replaceable>ipset</replaceable> where
                    <replaceable>ipset</replaceable> is the name of an ipset
                    and must be preceded by a plus sign ("+").</para>
                  </listitem>

                  <listitem>
                    <para>^<replaceable>country-code</replaceable> where
                    country-code is a two-character ISO-3661 country code
                    preceded by a caret ("^").</para>
                  </listitem>

                  <listitem>
                    <para>^<replaceable>country-code-list</replaceable> where
                    <replaceable>country-code-list</replaceable> is a
                    comma-separated list of up to 15 ISO-3661 country codes
                    enclosed in square brackets ("[...]").</para>
                  </listitem>

                  <listitem>
                    <para>The primary IP address of a firewall interface can
                    be specified by an ampersand ('&amp;') followed by the
                    logical name of the interface as found in the INTERFACE
                    column of <ulink
                    url="/manpages/shorewall-interfaces.html">shorewall-interfaces</ulink>
                    (5).</para>
                  </listitem>
                </itemizedlist>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>interface</replaceable>:<replaceable>address</replaceable>[,...]</term>

              <listitem>
                <para>This form combines the preceding two and requires that
                both the outgoing interface and destinationaddress
                match.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>exclusion</replaceable></term>

              <listitem>
                <para>This form matches if the host IP address does not match
                any of the entries in the exclusion (see <ulink
                url="shorewall-exclusion.html">shorewall-exclusion</ulink>(5)).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>zone</replaceable>:<replaceable>interface</replaceable>:<replaceable>exclusion</replaceable></term>

              <listitem>
                <para>This form matches packets to the named
                <replaceable>zone</replaceable> leaving through the specified
                <replaceable>interface</replaceable> where the destination
                address does not match any entry in the
                <replaceable>exclusion</replaceable>.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>[<replaceable>zone</replaceable>]:[<replaceable>server-IP</replaceable>][:<replaceable>port-or-port-range</replaceable>[:random]]</term>

              <listitem>
                <para>This form applies when the ACTION is DNAT[-] or
                REDIRECT[-]. The zone may be omitted in REDIRECT rules ($FW is
                assumed) and must be omitted in DNAT-, REDIRECT- and NONAT
                rules.</para>

                <para><replaceable role="bold">server-IP</replaceable> is not
                allowed in REDIRECT rules and may be omitted in DNAT[-] rules
                provided that <replaceable>port-or-port-range</replaceable> is
                included.</para>

                <itemizedlist>
                  <listitem>
                    <para>The IP address of the server to which the packet is
                    to be sent.</para>
                  </listitem>

                  <listitem>
                    <para>A range of IP address with the low and high address
                    separated by a dash (:"-"). Connections are distributed
                    among the IP addresses in the range.</para>
                  </listitem>
                </itemizedlist>

                <para>If <replaceable>server-IP </replaceable>is omitted in a
                DNAT[-] rule, only the destination port number is modified by
                the rule.</para>

                <para>port-or-port-range may be:</para>

                <itemizedlist>
                  <listitem>
                    <para>An integer port number in the range 1 -
                    65535.</para>
                  </listitem>

                  <listitem>
                    <para>The name of a service from
                    <filename>/etc/services</filename>.</para>
                  </listitem>

                  <listitem>
                    <para>A port range with the low and high integer port
                    numbers separated by a dash ("-"). Connections are
                    distributed among the ports in the range.</para>
                  </listitem>
                </itemizedlist>

                <para>If <emphasis role="bold">random</emphasis> is specified,
                port mapping will be randomized.</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>If the DEST <replaceable>zone</replaceable> is a bport zone,
          then either:<orderedlist numeration="loweralpha">
              <listitem>
                <para>the SOURCE must be <option>all[+][-]</option>, or</para>
              </listitem>

              <listitem>
                <para>the SOURCE <replaceable>zone</replaceable> must be
                another bport zone associated with the same bridge, or</para>
              </listitem>

              <listitem>
                <para>the SOURCE <replaceable>zone</replaceable> must be an
                ipv4 zone that is associated with only the same bridge.</para>
              </listitem>
            </orderedlist>Beginning with Shorewall 5.1.0, multiple
          <replaceable>dest-spec</replaceable>s may be listed, provided that
          extended forms of the source-spec are used:</para>

          <blockquote>
            <para><replaceable>zone</replaceable>:(<replaceable>interface</replaceable>)</para>

            <para><replaceable>zone</replaceable>:(<replaceable>address</replaceable>[,...])</para>

            <para>zone:(interface:address[,...])</para>

            <para><replaceable>zone</replaceable>:(<replaceable>exclusion</replaceable>)</para>

            <para><replaceable>zone</replaceable>:(<replaceable>interface</replaceable>:<replaceable>exclusion</replaceable>)</para>
          </blockquote>

          <para>Multiple <replaceable>dest-spec</replaceable>s are not
          permitted in DNAT[-] and REDIRECT[-] rules.</para>

          <para>Examples:</para>

          <variablelist>
            <varlistentry>
              <term>dmz:192.168.2.2</term>

              <listitem>
                <para>Host 192.168.2.2 in the DMZ</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:155.186.235.0/24</term>

              <listitem>
                <para>Subnet 155.186.235.0/24 on the Internet</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>loc:192.168.1.1,192.168.1.2</term>

              <listitem>
                <para>Hosts 192.168.1.1 and 192.168.1.2 in the local
                zone.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:192.0.2.11-192.0.2.17</term>

              <listitem>
                <para>Hosts 192.0.2.11-192.0.2.17 in the net zone.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:!192.0.2.11-192.0.2.17</term>

              <listitem>
                <para>All hosts in the net zone except for
                192.0.2.11-192.0.2.17.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:155.186.235.0/24!155.186.235.16/28</term>

              <listitem>
                <para>Subnet 155.186.235.0/24 on the Internet except for
                155.186.235.16/28</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>$FW:&amp;eth0</term>

              <listitem>
                <para>The primary IP address of eth0 in the firewall
                zone.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>loc,dmz</term>

              <listitem>
                <para>Both the <emphasis role="bold">loc</emphasis> and
                <emphasis role="bold">dmz</emphasis> zones.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>all!dmz</term>

              <listitem>
                <para>All but the <emphasis role="bold">dmz</emphasis>
                zone.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>net:^CN</term>

              <listitem>
                <para>China.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>dmz:192.168.10.4:25</term>

              <listitem>
                <para>Port 25 on server 192.168.10.4 in the dmz zone (DNAT
                rule).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>loc:(eth1:1.2.3.4,2.3.4.5),dmz:(eth2:5.6.7.8,9.10.11.12),net</term>

              <listitem>
                <para>Hosts 1.2.3.4 and 2.3.4.5 in the loc zone when the
                packet arrives through eth1 plus hosts 5.6.7.8 and 9.10.11.12
                in the dmz zone when the packet arrives through eth2 plus all
                of the net zone.</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">PROTO</emphasis>- {<emphasis
        role="bold">-</emphasis>|<emphasis
        role="bold">tcp:[!]syn</emphasis>|<emphasis
        role="bold">ipp2p</emphasis>|<emphasis
        role="bold">ipp2p:udp</emphasis>|<emphasis
        role="bold">ipp2p:all</emphasis>|<emphasis>protocol-number</emphasis>|<emphasis>protocol-name</emphasis>|<emphasis
        role="bold">all}</emphasis></term>

        <listitem>
          <para>Optional Protocol - <emphasis role="bold">ipp2p</emphasis>*
          requires ipp2p match support in your kernel and iptables. <emphasis
          role="bold">tcp:syn</emphasis> implies <emphasis
          role="bold">tcp</emphasis> plus the SYN flag must be set and the
          RST, ACK and FIN flags must be reset. Beginning with Shorewall
          5.1.3, you may also specify <emphasis
          role="bold">tcp:!syn</emphasis>, which matches if SYN is not set or
          if RST, ACK or FIN is set.</para>

          <para>Beginning with Shorewall 4.4.19, this column can contain a
          comma-separated list of protocol-numbers and/or protocol
          names.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DPORT</emphasis> - {<emphasis
        role="bold">-</emphasis>|<emphasis>port-name-number-or-range</emphasis>[<emphasis
        role="bold">,</emphasis><emphasis>port-name-number-or-range</emphasis>]...|+<replaceable>ipset</replaceable>}</term>

        <listitem>
          <para>Optional destination Ports. A comma-separated list of Port
          names (from services(5)), port numbers or port ranges; if the
          protocol is <emphasis role="bold">icmp</emphasis>, this column is
          interpreted as the destination icmp-type(s). ICMP types may be
          specified as a numeric type, a numeric type and code separated by a
          slash (e.g., 3/4), or a typename. See <ulink
          url="/configuration_file_basics.htm#ICMP">http://www.shorewall.net/configuration_file_basics.htm#ICMP</ulink>.
          Note that prior to Shorewall 4.4.19, only a single ICMP type may be
          listed.</para>

          <para>If the protocol is <emphasis role="bold">ipp2p</emphasis>,
          this column is interpreted as an ipp2p option without the leading
          "--" (example <emphasis role="bold">bit</emphasis> for bit-torrent).
          If no port is given, <emphasis role="bold">ipp2p</emphasis> is
          assumed.</para>

          <para>A port range is expressed as
          <emphasis>lowport</emphasis>:<emphasis>highport</emphasis>.</para>

          <para>This column is ignored if <emphasis
          role="bold">PROTO</emphasis> = <emphasis role="bold">all</emphasis>
          but must be entered if any of the following columns are supplied. In
          that case, it is suggested that this field contain a dash (<emphasis
          role="bold">-</emphasis>).</para>

          <para>If your kernel contains multi-port match support, then only a
          single Netfilter rule will be generated if in this list and the
          <emphasis role="bold">SPORT</emphasis> list below:</para>

          <para>1. There are 15 or less ports listed.</para>

          <para>2. No port ranges are included or your kernel and iptables
          contain extended multi-port match support.</para>

          <para>Beginning with Shorewall 4.6.0, an
          <replaceable>ipset</replaceable> name can be specified in this
          column. This is intended to be used with
          <firstterm>bitmap:port</firstterm> ipsets.</para>

          <para>This column was formerly labelled DEST PORT(S).</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">SPORT</emphasis> - {<emphasis
        role="bold">-</emphasis>|<emphasis>port-name-number-or-range</emphasis>[<emphasis
        role="bold">,</emphasis><emphasis>port-name-number-or-range</emphasis>]...|+<replaceable>ipset</replaceable>}</term>

        <listitem>
          <para>Optional port(s) used by the client. If omitted, any source
          port is acceptable. Specified as a comma- separated list of port
          names, port numbers or port ranges.</para>

          <para>Beginning with Shorewall 4.5.15, you may place '=' in this
          column, provided that the DPORT column is non-empty. This causes the
          rule to match when either the source port or the destination port in
          a packet matches one of the ports specified in DEST PORTS(S). Use of
          '=' requires multi-port match in your iptables and kernel.</para>

          <warning>
            <para>Unless you really understand IP, you should leave this
            column empty or place a dash (<emphasis role="bold">-</emphasis>)
            in the column. Most people who try to use this column get it
            wrong.</para>
          </warning>

          <para>If you don't want to restrict client ports but need to specify
          an <emphasis role="bold">ORIGDEST</emphasis> in the next column,
          then place "-" in this column.</para>

          <para>If your kernel contains multi-port match support, then only a
          single Netfilter rule will be generated if in this list and the
          <emphasis role="bold">DPORT</emphasis> list above:</para>

          <para>1. There are 15 or less ports listed.</para>

          <para>2. No port ranges are included or your kernel and iptables
          contain extended multi-port match support.</para>

          <para>Beginning with Shorewall 4.6.0, an
          <replaceable>ipset</replaceable> name can be specified in this
          column. This is intended to be used with
          <firstterm>bitmap:port</firstterm> ipsets.</para>

          <para>This column was formerly labelled SOURCE PORT(S).</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">ORIGDEST</emphasis> - [<emphasis
        role="bold">-</emphasis>|<emphasis>address</emphasis>[,<emphasis>address</emphasis>]...[<emphasis>exclusion</emphasis>]|<emphasis>exclusion</emphasis>]</term>

        <listitem>
          <para>Optional. If ACTION is <emphasis
          role="bold">DNAT</emphasis>[<emphasis role="bold">-</emphasis>] or
          <emphasis role="bold">REDIRECT</emphasis>[<emphasis
          role="bold">-</emphasis>] then if this column is included and is
          different from the IP address given in the <emphasis
          role="bold">DEST</emphasis> column, then connections destined for
          that address will be forwarded to the IP and port specified in the
          <emphasis role="bold">DEST</emphasis> column.</para>

          <para>A comma-separated list of addresses may also be used. This is
          most useful with the <emphasis role="bold">REDIRECT</emphasis>
          target where you want to redirect traffic destined for particular
          set of hosts. Finally, if the list of addresses begins with "!"
          (<emphasis>exclusion</emphasis>) then the rule will be followed only
          if the original destination address in the connection request does
          not match any of the addresses listed.</para>

          <para>Beginning with Shorewall 4.4.17, the primary IP address of a
          firewall interface can be specified by an ampersand ('&amp;')
          followed by the logical name of the interface as found in the
          INTERFACE column of <ulink
          url="/manpages/shorewall-interfaces.html">shorewall-interfaces</ulink>
          (5).</para>

          <para>For other actions, this column may be included and may contain
          one or more addresses (host or network) separated by commas. Address
          ranges are not allowed. When this column is supplied, rules are
          generated that require that the original destination address matches
          one of the listed addresses. This feature is most useful when you
          want to generate a filter rule that corresponds to a <emphasis
          role="bold">DNAT-</emphasis> or <emphasis
          role="bold">REDIRECT-</emphasis> rule. In this usage, the list of
          addresses should not begin with "!".</para>

          <para>It is also possible to specify a set of addresses then exclude
          part of those addresses. For example, <emphasis
          role="bold">192.168.1.0/24!192.168.1.16/28</emphasis> specifies the
          addresses 192.168.1.0-182.168.1.15 and 192.168.1.32-192.168.1.255.
          See <ulink
          url="/manpages/shorewall-exclusion.html">shorewall-exclusion</ulink>(5).</para>

          <para>See <ulink
          url="/PortKnocking.html">http://www.shorewall.net/PortKnocking.html</ulink>
          for an example of using an entry in this column with a user-defined
          action rule.</para>

          <para>This column was formerly labelled ORIGINAL DEST.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">RATE</emphasis> -
        <replaceable>limit</replaceable></term>

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

          <simplelist>
            <member>[<emphasis role="bold">-</emphasis>|[{<emphasis
            role="bold">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>You may optionally rate-limit the rule by placing a value in
          this column:</para>

          <para><emphasis>rate*</emphasis> is the number of connections per
          interval (<emphasis role="bold">sec</emphasis> or <emphasis
          role="bold">min</emphasis>) and <emphasis>burst</emphasis>* is the
          largest burst permitted. If no <emphasis>burst</emphasis> is given,
          a value of 5 is assumed. There may be no no white-space embedded in
          the specification.</para>

          <para>Example: <emphasis role="bold">10/sec:20</emphasis></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>s may be chosen by
          the user and specify a hash table to be used to count matching
          connections. If not given, the name <emphasis
          role="bold">shorewallN</emphasis> (where N is a unique integer) is
          assumed. Where more than one rule or POLICY specifies the same name,
          the connections counts for the rules 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>

          <para>In this example, the 'client' hash table will be used to
          enforce the per-source limit and the compiler will pick a unique
          name for the hash table that tracks the per-destination
          limit.</para>

          <para>This column was formerly labelled RATE LIMIT.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">USER</emphasis> - [<emphasis
        role="bold">!</emphasis>][<emphasis>user-name-or-number</emphasis>][<emphasis
        role="bold">:</emphasis><emphasis>group-name-or-number</emphasis>][,...]</term>

        <listitem>
          <para>This optional column may only be non-empty if the SOURCE is
          the firewall itself.</para>

          <para>When this column is non-empty, the rule applies only if the
          program generating the output is running under the effective
          <emphasis>user</emphasis> and/or <emphasis>group</emphasis>
          specified (or is NOT running under that id if "!" is given).</para>

          <para>Beginning with Shorewall 4.5.8, multiple user or group
          names/ids separated by commas may be specified.</para>

          <para>Examples:</para>

          <variablelist>
            <varlistentry>
              <term>joe</term>

              <listitem>
                <para>program must be run by joe</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>:kids</term>

              <listitem>
                <para>program must be run by a member of the 'kids'
                group</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>!:kids</term>

              <listitem>
                <para>program must not be run by a member of the 'kids'
                group</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>2001-2099</term>

              <listitem>
                <para>UIDs 2001 through 2099 (Shorewall 4.5.6 and
                later)</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>This column was formerly labelled USER/GROUP.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">MARK</emphasis> - [<emphasis
        role="bold">!</emphasis>]<emphasis>value</emphasis>[/<emphasis>mask</emphasis>][<emphasis
        role="bold">:C</emphasis>]</term>

        <listitem>
          <para>Defines a test on the existing packet or connection mark. The
          rule will match only if the test returns true.</para>

          <para>If you don't want to define a test but need to specify
          anything in the following columns, place a "-" in this field.</para>

          <variablelist>
            <varlistentry>
              <term>!</term>

              <listitem>
                <para>Inverts the test (not equal)</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis>value</emphasis></term>

              <listitem>
                <para>Value of the packet or connection mark.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis>mask</emphasis></term>

              <listitem>
                <para>A mask to be applied to the mark before testing.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">:C</emphasis></term>

              <listitem>
                <para>Designates a connection mark. If omitted, the packet
                mark's value is tested.</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>May be used to limit the number of simultaneous connections
          to/from each individual host or network to
          <replaceable>limit</replaceable> connections. Requires connlimit
          match in your kernel and iptables. While the limit is only checked
          on rules specifying CONNLIMIT, the number of current connections is
          calculated over all current connections from the SOURCE or
          DESTINATION host. By default, limiting is done by SOURCE host or
          net, but if the specification begins with <emphasis
          role="bold">d:</emphasis>, then limiting will be donw by destination
          host or net.</para>

          <para>By default, the limit is applied to each host 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>.
          When<option> !</option> is specified, the rule matches when the
          number of connection exceeds the
          <replaceable>limit</replaceable>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">TIME</emphasis> -
        <emphasis>timeelement</emphasis>[&amp;<emphasis>timeelement</emphasis>...]</term>

        <listitem>
          <para>May be used to limit the rule to a particular time period each
          day, to particular days of the week or month, or to a range defined
          by dates and times. Requires time match support in your kernel and
          iptables.</para>

          <para><replaceable>timeelement</replaceable> may be:</para>

          <variablelist>
            <varlistentry>
              <term>timestart=<replaceable>hh</replaceable>:<replaceable>mm</replaceable>[:<replaceable>ss</replaceable>]</term>

              <listitem>
                <para>Defines the starting time of day.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>timestop=<replaceable>hh</replaceable>:<replaceable>mm</replaceable>[:<replaceable>ss</replaceable>]</term>

              <listitem>
                <para>Defines the ending time of day.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>contiguous</term>

              <listitem>
                <para>Added in Shoreawll 5.0.12. When <emphasis
                role="bold">timestop</emphasis> is smaller than <emphasis
                role="bold">timestart</emphasis> value, match this as a single
                time period instead of distinct intervals.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>utc</term>

              <listitem>
                <para>Times are expressed in Greenwich Mean Time.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>localtz</term>

              <listitem>
                <para>Deprecated by the Netfilter team in favor of <emphasis
                role="bold">kerneltz</emphasis>. Times are expressed in Local
                Civil Time (default).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>kerneltz</term>

              <listitem>
                <para>Added in Shorewall 4.5.2. Times are expressed in Local
                Kernel Time (requires iptables 1.4.12 or later).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>weekdays=ddd[,ddd]...</term>

              <listitem>
                <para>where <replaceable>ddd</replaceable> is one of
                <option>Mon</option>, <option>Tue</option>,
                <option>Wed</option>, <option>Thu</option>,
                <option>Fri</option>, <option>Sat</option> or
                <option>Sun</option></para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>monthdays=dd[,dd],...</term>

              <listitem>
                <para>where <replaceable>dd</replaceable> is an ordinal day of
                the month</para>

                <para/>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>datestart=<replaceable>yyyy</replaceable>[-<replaceable>mm</replaceable>[-<replaceable>dd</replaceable>[<option>T</option><replaceable>hh</replaceable>[:<replaceable>mm</replaceable>[:<replaceable>ss</replaceable>]]]]]</term>

              <listitem>
                <para>Defines the starting date and time.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>datestop=<replaceable>yyyy</replaceable>[-<replaceable>mm</replaceable>[-<replaceable>dd</replaceable>[<option>T</option><replaceable>hh</replaceable>[:<replaceable>mm</replaceable>[:<replaceable>ss</replaceable>]]]]]</term>

              <listitem>
                <para>Defines the ending date and time.</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>Added in Shorewall 4.4.15. Not used in IPv4 configurations. If
          you with to supply a value for one of the later columns, enter '-'
          in this column.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">SWITCH -
        [!]<replaceable>switch-name</replaceable>[={0|1}]</emphasis></term>

        <listitem>
          <para>Added in Shorewall 4.4.24 and allows enabling and disabling
          the rule without requiring <command>shorewall
          restart</command>.</para>

          <para>The rule is enabled if the value stored in
          <filename>/proc/net/nf_condition/<replaceable>switch-name</replaceable></filename>
          is 1. The rule is disabled if that file contains 0 (the default). If
          '!' is supplied, the test is inverted such that the rule is enabled
          if the file contains 0.</para>

          <para>Within the <replaceable>switch-name</replaceable>, '@0' and
          '@{0}' are replaced by the name of the chain to which the rule is a
          added. The <replaceable>switch-name</replaceable> (after '@...'
          expansion) must begin with a letter and be composed of letters,
          decimal digits, underscores or hyphens. Switch names must be 30
          characters or less in length.</para>

          <para>Switches are normally <emphasis role="bold">off</emphasis>. To
          turn a switch <emphasis role="bold">on</emphasis>:</para>

          <simplelist>
            <member><command>echo 1 &gt;
            /proc/net/nf_condition/<replaceable>switch-name</replaceable></command></member>
          </simplelist>

          <para>To turn it <emphasis role="bold">off</emphasis> again:</para>

          <simplelist>
            <member><command>echo 0 &gt;
            /proc/net/nf_condition/<replaceable>switch-name</replaceable></command></member>
          </simplelist>

          <para>Switch settings are retained over <command>shorewall
          restart</command>.</para>

          <para>Beginning with Shorewall 4.5.10, when the
          <replaceable>switch-name</replaceable> is followed by
          <option>=0</option> or <option>=1</option>, then the switch is
          initialized to off or on respectively by the
          <command>start</command> command. Other commands do not affect the
          switch setting.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">HELPER</emphasis> - [helper]</term>

        <listitem>
          <para>Added in Shorewall 4.5.7.</para>

          <para>In the NEW section, causes the named conntrack
          <replaceable>helper</replaceable> to be associated with this
          connection; the contents of this column are ignored unless ACTION is
          ACCEPT*, DNAT* or REDIRECT*.</para>

          <para>In the RELATED section, will only match if the related
          connection has the named <replaceable>helper</replaceable>
          associated with it.</para>

          <para>The <replaceable>helper</replaceable> may be one of:</para>

          <simplelist>
            <member><option>amanda</option></member>

            <member><option>ftp</option></member>

            <member><option>irc</option></member>

            <member><option>netbios-ns</option></member>

            <member><option>pptp</option></member>

            <member><option>Q.931</option></member>

            <member><option>RAS</option></member>

            <member><option>sane</option></member>

            <member><option>sip</option></member>

            <member><option>snmp</option></member>

            <member><option>tftp</option></member>
          </simplelist>

          <para>If the HELPERS option is specified in <ulink
          url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5), then
          any module specified in this column must be listed in the HELPERS
          setting.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Examples</title>

    <variablelist>
      <varlistentry>
        <term>Example 1:</term>

        <listitem>
          <para>Accept SMTP requests from the DMZ to the internet</para>

          <programlisting>         #ACTION SOURCE  DEST      PROTO      DPORT   SPORT   ORIGDEST
         ACCEPT  dmz     net       tcp        smtp</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 2:</term>

        <listitem>
          <para>Forward all ssh and http connection requests from the internet
          to local system 192.168.1.3</para>

          <programlisting>        #ACTION SOURCE  DEST            PROTO   DPORT   SPORT   ORIGDEST
        DNAT    net     loc:192.168.1.3 tcp     ssh,http</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 3:</term>

        <listitem>
          <para>Forward all http connection requests from the internet to
          local system 192.168.1.3 with a limit of 3 per second and a maximum
          burst of 10<programlisting>        #ACTION SOURCE DEST             PROTO  DPORT SPORT   ORIGDEST RATE
        DNAT    net    loc:192.168.1.3  tcp    http  -       -        3/sec:10</programlisting></para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 4:</term>

        <listitem>
          <para>Redirect all locally-originating www connection requests to
          port 3128 on the firewall (Squid running on the firewall system)
          except when the destination address is 192.168.2.2</para>

          <programlisting>        #ACTION  SOURCE DEST      PROTO DPORT   SPORT   ORIGDEST
        REDIRECT loc    3128      tcp   www      -      !192.168.2.2</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 5:</term>

        <listitem>
          <para>All http requests from the internet to address 130.252.100.69
          are to be forwarded to 192.168.1.3</para>

          <programlisting>        #ACTION  SOURCE DEST            PROTO   DPORT   SPORT   ORIGDEST
        DNAT      net   loc:192.168.1.3 tcp     80      -       130.252.100.69</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 6:</term>

        <listitem>
          <para>You want to accept SSH connections to your firewall only from
          internet IP addresses 130.252.100.69 and 130.252.100.70</para>

          <programlisting>        #ACTION  SOURCE DEST            PROTO   DPORT   SPORT   ORIGDEST
        ACCEPT   net:130.252.100.69,130.252.100.70 \
                        $FW             tcp     22</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 7:</term>

        <listitem>
          <para>You wish to accept connections from the internet to your
          firewall on port 2222 and you want to forward them to local system
          192.168.1.3, port 22</para>

          <programlisting>        #ACTION  SOURCE DEST                PROTO   DPORT   SPORT   ORIGDEST
        DNAT     net    loc:192.168.1.3:22  tcp     2222</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 8:</term>

        <listitem>
          <para>You want to redirect connection requests to port 80 randomly
          to the port range 81-90.</para>

          <programlisting>        #ACTION  SOURCE DEST                PROTO DPORT   SPORT   ORIGDEST
        REDIRECT net    $FW::81-90:random   tcp   www</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 9:</term>

        <listitem>
          <para>Shorewall does not impose as much structure on the Netfilter
          rules in the 'nat' table as it does on those in the filter table. As
          a consequence, when using Shorewall versions before 4.1.4, care must
          be exercised when using DNAT and REDIRECT rules with zones defined
          with wildcard interfaces (those ending with '+'. Here is an
          example:</para>

          <para><ulink
          url="/manpages/shorewall-zones.html">shorewall-zones</ulink>(5):<programlisting>        #ZONE       TYPE    OPTIONS
        fw          firewall
        net         ipv4
        dmz         ipv4
        loc         ipv4</programlisting></para>

          <para><ulink
          url="/manpages/shorewall-interfaces.html">shorewall-interfaces</ulink>(5):<programlisting>        #ZONE       INTERFACE       BROADCAST      OPTIONS
        net         ppp0
        loc         eth1            detect
        dmz         eth2            detect
        -           ppp+                           # Addresses are assigned from 192.168.3.0/24</programlisting></para>

          <para><ulink
          url="/manpages/shorewall-hosts.html">shorewall-host</ulink>(5):<programlisting>        #ZONE       HOST(S)              OPTIONS
        loc         ppp+:192.168.3.0/24</programlisting></para>

          <para>rules:</para>

          <programlisting>        #ACTION     SOURCE          DEST       PROTO       DPORT
        REDIRECT    loc             3128       tcp         80                                                   </programlisting>

          <simpara>Note that it would have been tempting to simply define the
          loc zone entirely in shorewall-interfaces(8):</simpara>

          <para><programlisting>        #******************* INCORRECT *****************
        #ZONE       INTERFACE       BROADCAST      OPTIONS
        net         ppp0
        loc         eth1            detect
        loc         ppp+
        dmz         eth2</programlisting></para>

          <para>This would have made it impossible to run a
          internet-accessible web server in the DMZ because all traffic
          entering ppp+ interfaces would have been redirected to port 3128 on
          the firewall and there would have been no net-&gt;fw ACCEPT rule for
          that traffic.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 10:</term>

        <listitem>
          <para>Add the tuple (source IP, dest port, dest IP) of an incoming
          SSH connection to the ipset S:</para>

          <programlisting>        #ACTION                       SOURCE           DEST           PROTO       DPORT
        ADD(+S:dst,src,dst)           net              fw             tcp         22</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 11:</term>

        <listitem>
          <para>You wish to limit SSH connections from remote systems to 1/min
          with a burst of three (to allow for limited retry):</para>

          <programlisting>        #ACTION     SOURCE          DEST       PROTO       DPORT        SPORT     ORIGDEST         RATE
        SSH(ACCEPT) net             all        -           -            -         -                s:1/min:3</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 12:</term>

        <listitem>
          <para>Forward port 80 to dmz host $BACKUP if switch 'primary_down'
          is on.</para>

          <programlisting>        #ACTION     SOURCE          DEST        PROTO       DPORT        SPORT     ORIGDEST   RATE      USER      MARK    CONNLIMIT     TIME     HEADERS    SWITCH
        DNAT        net             dmz:$BACKUP tcp         80           -         -          -         -         -       -             -        -          primary_down</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 13:</term>

        <listitem>
          <para>Drop all email from the <emphasis>Anonymous Proxy</emphasis>
          and <emphasis>Satellite Provider</emphasis> address ranges:</para>

          <programlisting>        #ACTION                       SOURCE           DEST           PROTO       DPORT
        DROP                          net:^A1,A2       fw             tcp         25</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 14:</term>

        <listitem>
          <para>You want to generate your own rule involving iptables targets
          and matches not supported by Shorewall.</para>

          <programlisting>        #ACTION                       SOURCE           DEST           PROTO       DPORT
        INLINE                        $FW              net ; -p 6 -m mickey-mouse --name test -m set --match-set set1 src -m mickey-mouse --name test2 -j SECCTX --name test3</programlisting>

          <para>The above will generate the following iptables-restore
          input:</para>

          <programlisting>        -A fw2net -p 6 -m mickey-mouse --name test -m set --match-set set1 src -m mickey-mouse --name test2 -j SECCTX --name test3</programlisting>

          <para>Note that SECCTX must be defined as a builtin action in <ulink
          url="/manpages/shorewall-actions.html">shorewall-actions</ulink>(5):</para>

          <programlisting>        #ACTION            OPTIONS
        SECCTX             builtin</programlisting>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>FILES</title>

    <para>/etc/shorewall/rules</para>
  </refsect1>

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

    <para><ulink
    url="/ipsets.html">http://www.shorewall.net/ipsets.html</ulink></para>

    <para><ulink
    url="/configuration_file_basics.htm#Pairs">http://www.shorewall.net/configuration_file_basics.htm#Pairs</ulink></para>

    <para><ulink
    url="/shorewall_logging.html">http://www.shorewall.net/shorewall_logging.html</ulink></para>

    <para>shorewall(8), shorewall-accounting(5), shorewall-actions(5),
    shorewall-blacklist(5), shorewall-blrules(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.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>