shorewall_code/Shorewall/manpages/shorewall-arprules.xml

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

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

  <refnamediv>
    <refname>arprules</refname>

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

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

  <refsect1>
    <title>Description</title>

    <para>This file was added in Shorwall 4.5.12 and is used to describe
    low-level rules managed by arptables (8). These rules only affect Address
    Resolution Protocol (ARP), Reverse Address Resolution Protocol (RARP) and
    Dynamic Reverse Address Resolution Protocol (DRARP) frames.</para>

    <para>The columns in the file are as shown below. MAC addresses are
    specified normally (6 hexidecimal numbers separated by colons).</para>

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

        <listitem>
          <para>Describes the action to take when a frame matches the criteria
          in the other columns. Possible values are:</para>

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

              <listitem>
                <para>This is the default action if no rules matches a frame;
                it lets the frame go through.</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>Causes the frame to be dropped.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">SNAT:</emphasis><replaceable>ip-address</replaceable></term>

              <listitem>
                <para>Modifies the source IP address to the specified
                <replaceable>ip-address</replaceable>.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">DNAT:</emphasis><replaceable>ip-address</replaceable></term>

              <listitem>
                <para>Modifies the destination IP address to the specified
                <replaceable>ip-address</replaceable>.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">SMAT:</emphasis><replaceable>mac-address</replaceable></term>

              <listitem>
                <para>Modifies the source MAC address to the specified
                <replaceable>mac-address</replaceable>.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">DMAT:</emphasis><replaceable>mac-address</replaceable></term>

              <listitem>
                <para>Modifies the destination MAC address to the specified
                <replaceable>mac-address</replaceable>.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">SNATC:</emphasis><replaceable>ip-address</replaceable></term>

              <listitem>
                <para>Like SNAT except that the frame is then passed to the
                next rule.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">DNATC:</emphasis><replaceable>ip-address</replaceable></term>

              <listitem>
                <para>Like DNAT except that the frame is then passed to the
                next rule.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">SMATC:</emphasis><replaceable>mac-address</replaceable></term>

              <listitem>
                <para>Like SMAT except that the frame is then passed to the
                next rule.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis
              role="bold">DMATC:</emphasis><replaceable>mac-address</replaceable></term>

              <listitem>
                <para>Like DMAT except that the frame is then passed to the
                next rule.</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">SOURCE</emphasis> - <emphasis
        role="bold">[<replaceable>interface</replaceable>[:[!]<replaceable>ipaddress</replaceable>[/ip<replaceable>mask</replaceable>][:[!]<replaceable>macaddress</replaceable>[/<replaceable>macmask</replaceable>]]]]</emphasis></term>

        <listitem>
          <para>Where</para>

          <variablelist>
            <varlistentry>
              <term><replaceable>interface</replaceable></term>

              <listitem>
                <para>Is an interface defined in
                shorewall-interfaces(5).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>ipaddress</replaceable></term>

              <listitem>
                <para>is an IPv4 address. DNS names are not allowed.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>ipmask</replaceable></term>

              <listitem>
                <para>specifies a mask to be applied to
                <replaceable>ipaddress</replaceable>.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>macaddress</replaceable></term>

              <listitem>
                <para>The source MAC address.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>macmask</replaceable></term>

              <listitem>
                <para>Mask for MAC address; must be specified as 6 hexidecimal
                numbers separated by colons.</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>When '!' is specified, the test is inverted.</para>

          <para>If not specified, matches only frames originating on the
          firewall itself.</para>

          <caution>
            <para>Either SOURCE or DEST must be specified.</para>
          </caution>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DEST</emphasis> - <emphasis
        role="bold">[<replaceable>interface</replaceable>[:[!]<replaceable>ipaddress</replaceable>[/ip<replaceable>mask</replaceable>][:[!]<replaceable>macaddress</replaceable>[/<replaceable>macmask</replaceable>]]]]</emphasis></term>

        <listitem>
          <para>Where</para>

          <variablelist>
            <varlistentry>
              <term><replaceable>interface</replaceable></term>

              <listitem>
                <para>Is an interface defined in
                shorewall-interfaces(5).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>ipaddress</replaceable></term>

              <listitem>
                <para>is an IPv4 address. DNS Names are not allowed.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>ipmask</replaceable></term>

              <listitem>
                <para>specifies a mask to be applied to frame
                addresses.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>macaddress</replaceable></term>

              <listitem>
                <para>The destination MAC address.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><replaceable>macmask</replaceable></term>

              <listitem>
                <para>Mask for MAC address; must be specified as 6 hexidecimal
                numbers separated by colons.</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>When '!' is specified, the test is inverted and the rule
          matches frames which do not match the specified address/mask.</para>

          <para>If not specified, matches only frames originating on the
          firewall itself.</para>

          <para>If both SOURCE and DEST are specified, then both interfaces
          must be bridge ports on the same bridge.</para>

          <caution>
            <para>Either SOURCE or DEST must be specified.</para>
          </caution>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>ARP OPCODE - [[!]<replaceable>opcode</replaceable>]</term>

        <listitem>
          <para>Optional. Describes the type of frame. Possible
          <replaceable>opcode</replaceable> values are:</para>

          <variablelist>
            <varlistentry>
              <term>1</term>

              <listitem>
                <para>ARP Request</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>2</term>

              <listitem>
                <para>ARP Reply</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>3</term>

              <listitem>
                <para>RARP Request</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>4</term>

              <listitem>
                <para>RARP Reply</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>5</term>

              <listitem>
                <para>Dynamic RARP Request</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>6</term>

              <listitem>
                <para>Dynamic RARP Reply</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>7</term>

              <listitem>
                <para>Dynamic RARP Error</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>8</term>

              <listitem>
                <para>InARP Request</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>9</term>

              <listitem>
                <para>ARP NAK</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>When '!' is specified, the test is inverted and the rule
          matches frames which do not match the specifed
          <replaceable>opcode</replaceable>.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Example</title>

    <para>The eth1 interface has both a pubiic IP address and a private
    address (10.1.10.11/24). When sending ARP requests to 10.1.10.0/24, use
    the private address as the IP source:</para>

    <programlisting>#ACTION                SOURCE                  DEST                ARP OPCODE
SNAT:10.1.10.11        -                       eth1:10.1.10.0/24   1</programlisting>
  </refsect1>

  <refsect1>
    <title>FILES</title>

    <para>/etc/shorewall/arprules</para>
  </refsect1>
</refentry>