shorewall_code/Shorewall/manpages/shorewall-exclusion.xml

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

    <manvolnum>5</manvolnum>

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

  <refnamediv>
    <refname>exclusion</refname>

    <refpurpose>Exclude a set of hosts from a definition in a shorewall
    configuration file.</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <arg choice="plain"
      rep="repeat"><option>!</option><replaceable>address-or-range</replaceable>[,<replaceable>address-or-range</replaceable>]</arg>
    </cmdsynopsis>

    <cmdsynopsis>
      <arg choice="plain"
      rep="repeat"><option>!</option><replaceable>zone-name</replaceable>[,<replaceable>zone-name</replaceable>]</arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>The first form of exclusion is used when you wish to exclude one or
    more addresses from a definition. An exclamation point is followed by a
    comma-separated list of addresses. The addresses may be single host
    addresses (e.g., 192.168.1.4) or they may be network addresses in CIDR
    format (e.g., 192.168.1.0/24). If your kernel and iptables include iprange
    support, you may also specify ranges of ip addresses of the form
    <emphasis>lowaddress</emphasis>-<emphasis>highaddress</emphasis></para>

    <para>No embedded white-space is allowed.</para>

    <para>Exclusion can appear after a list of addresses and/or address
    ranges. In that case, the final list of address is formed by taking the
    first list and then removing the addresses defined in the
    exclusion.</para>

    <para>Beginning in Shorewall 4.4.13, the second form of exclusion is
    allowed after <emphasis role="bold">all</emphasis> and <emphasis
    role="bold">any</emphasis> in the SOURCE and DEST columns of <ulink
    url="shorewall-rules.html">shorewall-rules</ulink>(5). It allows
    you to omit arbitrary zones from the list generated by those key
    words.</para>

    <warning>
      <para>If you omit a sub-zone and there is an explicit or explicit
      CONTINUE policy, a connection to/from that zone can still be matched by
      the rule generated for a parent zone.</para>

      <para>For example:</para>

      <blockquote>
        <para>/etc/shorewall/zones:</para>

        <programlisting>#ZONE          TYPE
z1             ip
z2:z1          ip
...</programlisting>

        <para>/etc/shorewall/policy:</para>

        <programlisting>#SOURCE         DEST          POLICY
z1              net           CONTINUE
z2              net           REJECT</programlisting>

        <para>/etc/shorewall/rules:</para>

        <programlisting>#ACTION         SOURCE        DEST        PROTO         DPORT
ACCEPT          all!z2        net         tcp           22</programlisting>

        <para>In this case, SSH connections from <emphasis
        role="bold">z2</emphasis> to <emphasis role="bold">net</emphasis> will
        be accepted by the generated <emphasis role="bold">z1</emphasis> to
        net ACCEPT rule.</para>
      </blockquote>
    </warning>

    <para>In most contexts, ipset names can be used as an
    <replaceable>address-or-range</replaceable>. Beginning with Shorewall
    4.4.14, ipset lists enclosed in +[...] may also be included (see <ulink
    url="shorewall-ipsets.html">shorewall-ipsets</ulink> (5)). The
    semantics of these lists when used in an exclusion are as follows:</para>

    <itemizedlist>
      <listitem>
        <para>!+[<replaceable>set1</replaceable>,<replaceable>set2</replaceable>,...<replaceable>setN</replaceable>]
        produces a packet match if the packet does not match at least one of
        the sets. In other words, it is like NOT match
        <replaceable>set1</replaceable> OR NOT match
        <replaceable>set2</replaceable> ... OR NOT match
        <replaceable>setN</replaceable>.</para>
      </listitem>

      <listitem>
        <para>+[!<replaceable>set1</replaceable>,!<replaceable>set2</replaceable>,...!<replaceable>setN</replaceable>]
        produces a packet match if the packet does not match any of the sets.
        In other words, it is like NOT match <replaceable>set1</replaceable>
        AND NOT match <replaceable>set2</replaceable> ... AND NOT match
        <replaceable>setN</replaceable>.</para>
      </listitem>
    </itemizedlist>
  </refsect1>

  <refsect1>
    <title>Examples</title>

    <variablelist>
      <varlistentry>
        <term>IPv4 Example 1 - All IPv4 addresses except 192.168.3.4</term>

        <listitem>
          <para>!192.168.3.4</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>IPv4 Example 2 - All IPv4 addresses except the network
        192.168.1.0/24 and the host 10.2.3.4</term>

        <listitem>
          <para>!192.168.1.0/24,10.1.3.4</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>IPv4 Example 3 - All IPv4 addresses except the range
        192.168.1.3-192.168.1.12 and the network 10.0.0.0/8</term>

        <listitem>
          <para>!192.168.1.3-192.168.1.12,10.0.0.0/8</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>IPv4 Example 4 - The network 192.168.1.0/24 except hosts
        192.168.1.3 and 192.168.1.9</term>

        <listitem>
          <para>192.168.1.0/24!192.168.1.3,192.168.1.9</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>Example 5 - All parent zones except loc</term>

        <listitem>
          <para>any!loc</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>FILES</title>

    <para>/etc/shorewall/hosts</para>

    <para>/etc/shorewall/masq</para>

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

    <para>/etc/shorewall/tcrules</para>
  </refsect1>

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

    <para>shorewall(8)</para>
  </refsect1>
</refentry>