shorewall_code/Shorewall/manpages/shorewall-conntrack.xml

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<refentry>
  <refmeta>
    <refentrytitle>shorewall6-conntrack</refentrytitle>

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

  <refnamediv>
    <refname>conntrack</refname>

    <refpurpose>shorewall conntrack file</refpurpose>
  </refnamediv>

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

  <refsect1>
    <title>Description</title>

    <para>The original intent of the <emphasis role="bold">notrack</emphasis>
    file was to exempt certain traffic from Netfilter connection tracking.
    Traffic matching entries in the file were not to be tracked.</para>

    <para>The role of the file was expanded in Shorewall 4.4.27 to include all
    rules that can be added in the Netfilter <emphasis
    role="bold">raw</emphasis> table. In 4.5.7, the file's name was changed to
    <emphasis role="bold">conntrack</emphasis>.</para>

    <para>The file supports two different column layouts: FORMAT 1 and FORMAT
    2, FORMAT 1 being the default. The two differ in that FORMAT 2 has an
    additional leading ACTION column. When an entry in the file of this form
    is encountered, the format of the following entries are assumed to be of
    the specified <replaceable>format</replaceable>.</para>

    <simplelist>
      <member><emphasis role="bold">FORMAT</emphasis>
      <replaceable>format</replaceable></member>
    </simplelist>

    <para>where <replaceable>format</replaceable> is either <emphasis
    role="bold">1</emphasis> or <emphasis role="bold">2</emphasis>.</para>

    <para>Comments may be attached to Netfilter rules generated from entries
    in this file through the use of COMMENT lines. These lines begin with the
    word COMMENT; the remainder of the line is treated as a comment which is
    attached to subsequent rules until another COMMENT line is found or until
    the end of the file is reached. To stop adding comments to rules, use a
    line with only the word COMMENT.</para>

    <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">NOTRACK</emphasis>|<emphasis
        role="bold">CT</emphasis>:<emphasis
        role="bold">helper</emphasis>:<replaceable>name</replaceable>[(<replaceable>arg</replaceable>=<replaceable>val</replaceable>[,...])|<emphasis
        role="bold">CT:notrack</emphasis>}</term>

        <listitem>
          <para>This column is only present when FORMAT = 2. Values other than
          NOTRACK require <firstterm>CT Target </firstterm>support in your
          iptables and kernel.</para>

          <itemizedlist>
            <listitem>
              <para><option>NOTRACK</option> or
              <option>CT:notrack</option></para>

              <para>Disables connection tracking for this packet.</para>
            </listitem>

            <listitem>
              <para><option>helper</option>:<replaceable>name</replaceable></para>

              <para>Attach the helper identified by the
              <replaceable>name</replaceable> to this connection. This is more
              flexible than loading the conntrack helper with preset
              ports.</para>

              <para>At this writing, the available helpers are:</para>

              <variablelist>
                <varlistentry>
                  <term>amanda</term>

                  <listitem>
                    <para>Requires that the amanda netfilter helper is
                    present.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>ftp</term>

                  <listitem>
                    <para>Requires that the FTP netfilter helper is
                    present.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>irc</term>

                  <listitem>
                    <para>Requires that the IRC netfilter helper is
                    present.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>netbios-ns</term>

                  <listitem>
                    <para>Requires that the netbios_ns (sic) helper is
                    present.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>RAS and Q.931</term>

                  <listitem>
                    <para>These require that the H323 netfilter helper is
                    present.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>pptp</term>

                  <listitem>
                    <para>Requires that the pptp netfilter helper is
                    present.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>sane</term>

                  <listitem>
                    <para>Requires that the SANE netfilter helper is
                    present.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>sip</term>

                  <listitem>
                    <para>Requires that the SIP netfilter helper is
                    present.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>snmp</term>

                  <listitem>
                    <para>Requires that the SNMP netfilter helper is
                    present.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>tftp</term>

                  <listitem>
                    <para>Requires that the TFTP netfilter helper is
                    present.</para>
                  </listitem>
                </varlistentry>
              </variablelist>

              <para>May be followed by an option list of
              <replaceable>arg</replaceable>=<replaceable>val</replaceable>
              pairs in parentheses:</para>

              <itemizedlist>
                <listitem>
                  <para><option>ctevents</option>=<replaceable>event</replaceable>[,...]</para>

                  <para>Only generate the specified conntrack events for this
                  connection. Possible event types are: <emphasis
                  role="bold">new</emphasis>, <emphasis
                  role="bold">related</emphasis>, <emphasis
                  role="bold">destroy</emphasis>, <emphasis
                  role="bold">reply</emphasis>, <emphasis
                  role="bold">assured</emphasis>, <emphasis
                  role="bold">protoinfo</emphasis>, <emphasis
                  role="bold">helper</emphasis>, <emphasis
                  role="bold">mark</emphasis> (this is connection mark, not
                  packet mark), <emphasis role="bold">natseqinfo</emphasis>,
                  and <emphasis role="bold">secmark</emphasis>. If more than
                  one <emphasis>event</emphasis> is listed, the
                  <replaceable>event</replaceable> list must be enclosed in
                  parentheses (e.g., ctevents=(new,related)).</para>
                </listitem>

                <listitem>
                  <para><option>expevents</option><option>=new</option></para>

                  <para>Only generate a <emphasis role="bold">new</emphasis>
                  expectation events for this connection.</para>
                </listitem>
              </itemizedlist>
            </listitem>
          </itemizedlist>

          <para>When FORMAT = 1, this column is not present and the rule is
          processed as if NOTRACK had been entered in this column.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>SOURCE ‒
        {<emphasis>zone</emphasis>[:<emphasis>interface</emphasis>][:<emphasis>address-list</emphasis>]|COMMENT}</term>

        <listitem>
          <para>where <replaceable>zone</replaceable> is the name of a zone,
          <replaceable>interface</replaceable> is an interface to that zone,
          and <replaceable>address-list</replaceable> is a comma-separated
          list of addresses (may contain exclusion - see <ulink
          url="shorewall-exclusion.html">shorewall-exclusion</ulink>
          (5)).</para>

          <para>Beginning with Shorewall 4.5.7, <option>all</option> can be
          used as the <replaceable>zone</replaceable> name to mean
          <firstterm>all zones</firstterm>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>DEST ‒
        [<replaceable>interface</replaceable>|<replaceable>address-list</replaceable>]</term>

        <listitem>
          <para>where <replaceable>interface</replaceable> is the name of a
          network interface and <replaceable>address-list</replaceable> is a
          comma-separated list of addresses (may contain exclusion - see
          <ulink url="shorewall-exclusion.html">shorewall-exclusion</ulink>
          (5)). If an interface is given:</para>

          <itemizedlist>
            <listitem>
              <para>It must be up and configured with an IPv4 address when
              Shorewall is started or restarted.</para>
            </listitem>

            <listitem>
              <para>All routes out of the interface must be configured when
              Shorewall is started or restarted.</para>
            </listitem>

            <listitem>
              <para>Default routes out of the interface will result in a
              warning message and will be ignored.</para>
            </listitem>
          </itemizedlist>

          <para>These restrictions are because Netfilter doesn't support
          NOTRACK rules that specify a destination interface (these rules are
          applied before packets are routed and hence the destination
          interface is unknown). Shorewall uses the routes out of the
          interface to replace the interface with an address list
          corresponding to the networks routed out of the named
          interface.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>PROTO ‒
        <replaceable>protocol-name-or-number</replaceable></term>

        <listitem>
          <para>A protocol name from <filename>/etc/protocols</filename> or a
          protocol number.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>DEST PORT(S) (dport) - port-number/service-name-list</term>

        <listitem>
          <para>A comma-separated list of port numbers and/or service names
          from <filename>/etc/services</filename>. May also include port
          ranges of the form
          <replaceable>low-port</replaceable>:<replaceable>high-port</replaceable>
          if your kernel and iptables include port range support.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>SOURCE PORT(S) (sport) - port-number/service-name-list</term>

        <listitem>
          <para>A comma-separated list of port numbers and/or service names
          from <filename>/etc/services</filename>. May also include port
          ranges of the form
          <replaceable>low-port</replaceable>:<replaceable>high-port</replaceable>
          if your kernel and iptables include port range support.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>USER/GROUP (user) ‒
        [<replaceable>user</replaceable>][:<replaceable>group</replaceable>]</term>

        <listitem>
          <para>May only be specified if the SOURCE
          <replaceable>zone</replaceable> is $FW. Specifies the effective user
          id and or group id of the process sending the traffic.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>EXAMPLE</title>

    <programlisting>#ACTION                       SOURCE            DEST               PROTO            DEST              SOURCE              USER/GROUP
#                                                                                   PORT(S)           PORT(S)
CT:helper:ftp(expevents=new)  fw                -                  tcp              21              </programlisting>
  </refsect1>

  <refsect1>
    <title>FILES</title>

    <para>/etc/shorewall/notrack</para>
  </refsect1>

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

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

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