shorewall_code/manpages6/shorewall6-tcrules.xml

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

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

  <refnamediv>
    <refname>tcrules</refname>

    <refpurpose>Shorewall6 Packet Marking rules file</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>/etc/shorewall6/tcrules</command>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>Entries in this file cause packets to be marked as a means of
    classifying them for traffic control or policy routing.</para>

    <important>
      <para>Unlike rules in the <ulink
      url="shorewall6-rules.html">shorewall6-rules</ulink>(5) file, evaluation
      of rules in this file will continue after a match. So the final mark for
      each packet will be the one assigned by the LAST tcrule that
      matches.</para>

      <para>If you use multiple internet providers with the 'track' option, in
      /etc/shorewall6/providers be sure to read the restrictions at <ulink
      url="http://shorewall.net/MultiISP.html">http://shorewall.net/MultiISP.html</ulink>.</para>
    </important>

    <para>The columns in the file are as follows (where the column name is
    followed by a different name in parentheses, the different name is used in
    the alternate specification syntax).</para>

    <variablelist>
      <varlistentry>
        <term><emphasis role="bold">MARK/CLASSIFY</emphasis> -
        <replaceable>mark</replaceable></term>

        <listitem>
          <para><replaceable>mark</replaceable> may assume one of the
          following values.</para>

          <orderedlist numeration="arabic">
            <listitem>
              <para>A mark <emphasis>value</emphasis> which is an integer in
              the range 1-255.</para>

              <para>Normally will set the mark value. 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 ip6tables; neither may be used with
              connection marks (see below).</para>

              <para>May optionally be followed by <emphasis
              role="bold">:P</emphasis>, <emphasis role="bold">:F</emphasis>
              or <emphasis role="bold">:T</emphasis>, <emphasis role="bold">:I
              </emphasis>where<emphasis role="bold"> :P</emphasis> indicates
              that marking should occur in the PREROUTING chain, <emphasis
              role="bold">:F</emphasis> indicates that marking should occur in
              the FORWARD chain, <emphasis role="bold">:I </emphasis>indicates
              that marking should occur in the INPUT chain (added in Shorewall
              4.4.13) and <emphasis role="bold">:T</emphasis> indicates that
              marking should occur in the POSTROUTING chain. If neither
              <emphasis role="bold">:P</emphasis>, <emphasis
              role="bold">:F</emphasis> nor <emphasis
              role="bold">:T</emphasis> follow the mark value then the chain
              is determined as follows:</para>

              <para>- If the SOURCE is <emphasis
              role="bold">$FW</emphasis>[<emphasis
              role="bold">:</emphasis><emphasis>address-or-range</emphasis>[,<emphasis>address-or-range</emphasis>]...],
              then the rule is inserted into the OUTPUT chain. The behavior
              changed in Shorewall6-perl 4.1. Only high mark values may be
              assigned in this case. Packet marking rules for traffic shaping
              of packets originating on the firewall must be coded in the
              POSTROUTING chain (see below).</para>

              <para>- Otherwise, the chain is determined by the setting of
              MARK_IN_FORWARD_CHAIN in <ulink
              url="shorewall6.conf.html">shorewall6.conf</ulink>(5).</para>

              <para>Please note that <emphasis role="bold">:I</emphasis> is
              included for completeness and affects neither traffic shaping
              nor policy routing.</para>

              <para>If your kernel and ip6tables include CONNMARK support then
              you can also mark the connection rather than the packet.</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). The mark and optional mask are then
              followed by one of:+</para>

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

                  <listitem>
                    <para>Mark the connection in the chain determined by the
                    setting of MARK_IN_FORWARD_CHAIN</para>
                  </listitem>
                </varlistentry>

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

                  <listitem>
                    <para>Mark the connection in the FORWARD chain</para>
                  </listitem>
                </varlistentry>

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

                  <listitem>
                    <para>Mark the connection in the PREROUTING chain.</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>CT</term>

                  <listitem>
                    <para>Mark the connection in the POSTROUTING chain</para>
                  </listitem>
                </varlistentry>

                <varlistentry>
                  <term>CI</term>

                  <listitem>
                    <para>Mark the connection in the INPUT chain. This option
                    is included for completeness and has no applicability to
                    traffic shaping or policy routing.</para>
                  </listitem>
                </varlistentry>
              </variablelist>

              <para><emphasis role="bold">Special considerations for If
              HIGH_ROUTE_MARKS=Yes in <ulink
              url="shorewall6.conf.html">shorewall6.conf</ulink>(5</emphasis>).</para>

              <para>If HIGH_ROUTE_MARKS=Yes, then you may also specify a value
              in the range 0x0100-0xFF00 with the low-order byte being zero.
              Such values may only be used in the PREROUTING chain (value
              followed by <emphasis role="bold">:P</emphasis> or you have set
              MARK_IN_FORWARD_CHAIN=No in <ulink
              url="shorewall6.conf.html">shorewall6.conf</ulink>(5) and have
              not followed the value with <option>:F</option>) or the OUTPUT
              chain (SOURCE is <emphasis role="bold">$FW</emphasis>). With
              HIGH_ROUTE_MARKS=Yes, non-zero mark values less that 256 are not
              permitted. Shorewall6 prohibits non-zero mark values less that
              256 in the OUTPUT chain when HIGH_ROUTE_MARKS=Yes. While earlier
              versions allow such values in the OUTPUT chain, it is strongly
              recommended that with HIGH_ROUTE_MARKS=Yes, you use the
              POSTROUTING chain to apply traffic shaping
              marks/classification.</para>
            </listitem>

            <listitem>
              <para>A classification Id (classid) of the form
              <emphasis>major</emphasis>:<emphasis>minor</emphasis> where
              <emphasis>major</emphasis> and <emphasis>minor</emphasis> are
              integers. Corresponds to the 'class' specification in these
              traffic shaping modules:</para>

              <programlisting>       atm
       cbq
       dsmark
       pfifo_fast
       htb
       prio</programlisting>

              <para>Classification occurs in the POSTROUTING chain except when
              the <emphasis role="bold">SOURCE</emphasis> is <emphasis
              role="bold">$FW</emphasis>[:<emphasis>address</emphasis>] in
              which case classification occurs in the OUTPUT chain.</para>

              <para>When using Shorewall6's built-in traffic shaping tool, the
              <emphasis>major</emphasis> class is the device number (the first
              device in <ulink
              url="shorewall6-tcdevices.html">shorewall6-tcdevices</ulink>(5)
              is major class 1, the second device is major class 2, and so on)
              and the <emphasis>minor</emphasis> class is the class's MARK
              value in <ulink
              url="shorewall6-tcclasses.html">shorewall6-tcclasses</ulink>(5)
              preceded by the number 1 (MARK 1 corresponds to minor class 11,
              MARK 5 corresponds to minor class 15, MARK 22 corresponds to
              minor class 122, etc.).</para>
            </listitem>

            <listitem>
              <para><emphasis
              role="bold">RESTORE</emphasis>[/<emphasis>mask</emphasis>] --
              restore the packet's mark from the connection's mark using the
              supplied mask if any. Your kernel and ip6tables must include
              CONNMARK support.</para>

              <para>As in 1) above, may be followed by <emphasis
              role="bold">:P</emphasis> or <emphasis
              role="bold">:F</emphasis></para>
            </listitem>

            <listitem>
              <para><emphasis
              role="bold">SAVE</emphasis>[/<emphasis>mask</emphasis>] -- save
              the packet's mark to the connection's mark using the supplied
              mask if any. Your kernel and ip6tables must include CONNMARK
              support.</para>

              <para>As in 1) above, may be followed by <emphasis
              role="bold">:P</emphasis> or <emphasis
              role="bold">:F</emphasis></para>
            </listitem>

            <listitem>
              <para><emphasis role="bold">CONTINUE</emphasis> Don't process
              any more marking rules in the table.</para>

              <para>As in 1) above, may be followed by <emphasis
              role="bold">:P</emphasis> or <emphasis
              role="bold">:F</emphasis>. Currently, CONTINUE may not be used
              with <emphasis>exclusion</emphasis> (see the SOURCE and DEST
              columns below); that restriction will be removed when
              ip6tables/Netfilter provides the necessary support.</para>
            </listitem>

            <listitem>
              <para><emphasis role="bold">SAME</emphasis> (Added in Shorewall
              4.3.5) -- Some websites run applications that require multiple
              connections from a client browser. Where multiple 'balanced'
              providers are configured, this can lead to problems when some of
              the connections are routed through one provider and some through
              another. The SAME target allows you to work around that problem.
              SAME may be used in the PREROUTING and OUTPUT chains. When used
              in PREROUTING, it causes matching connections from an individual
              local system to all use the same provider. For example:
              <programlisting>#MARK/            SOURCE         DEST         PROTO      DEST
#CLASSIFY                                                PORT(S)
SAME:P            192.168.1.0/24 0.0.0.0/0    tcp        80,443</programlisting>
              If a host in 192.168.1.0/24 attempts a connection on TCP port 80
              or 443 and it has sent a packet on either of those ports in the
              last five minutes then the new connection will use the same
              provider as the connection over which that last packet was
              sent.</para>

              <para>When used in the OUTPUT chain, it causes all matching
              connections to an individual remote system to all use the same
              provider. For example:<programlisting>#MARK/            SOURCE         DEST         PROTO      DEST
#CLASSIFY                                                PORT(S)
SAME              $FW            0.0.0.0/0    tcp        80,443</programlisting>
              If the firewall attempts a connection on TCP port 80 or 443 and
              it has sent a packet on either of those ports in the last five
              minutes to the same remote system then the new connection will
              use the same provider as the connection over which that last
              packet was sent.</para>
            </listitem>

            <listitem>
              <para><emphasis role="bold">COMMENT</emphasis> -- 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 <command>shorewall6
              show mangle</command></para>

              <para>To stop the comment from being attached to further rules,
              simply include COMMENT on a line by itself.</para>
            </listitem>

            <listitem>
              <para><emphasis
              role="bold">TPROXY</emphasis>(<replaceable>mark</replaceable>[/<replaceable>mask</replaceable>][,[<replaceable>port</replaceable>][,[<replaceable>address</replaceable>]]])</para>

              <para>Transparently redirects a packet without altering the IP
              header. Requires a local provider to be defined in <ulink
              url="shorewall6-providers.html">shorewall6-providers</ulink>(5).</para>

              <para>There are three parameters to TPROXY - only the first
              (mark) is required:</para>

              <itemizedlist>
                <listitem>
                  <para><replaceable>mark</replaceable> - the MARK value
                  corresponding to the local provider in <ulink
                  url="shorewall6-providers.html">shorewall6-providers</ulink>(5).</para>
                </listitem>

                <listitem>
                  <para><replaceable>port</replaceable> - the port on which
                  the proxy server is listening. If omitted, the original
                  destination port.</para>
                </listitem>

                <listitem>
                  <para><replaceable>address</replaceable> - a local (to the
                  firewall) IP address on which the proxy server is listening.
                  If omitted, the IP address of the interface on which the
                  request arrives.</para>
                </listitem>
              </itemizedlist>
            </listitem>

            <listitem>
              <para><emphasis role="bold">HL</emphasis>([<emphasis
              role="bold">-</emphasis>|<emphasis
              role="bold">+</emphasis>]<replaceable>number</replaceable>)</para>

              <para>Added in Shorewall 4.4.24. May be option followed by
              <emphasis role="bold">:F</emphasis> but the resulting rule is
              always added to the FORWARD chain. If <emphasis
              role="bold">+</emphasis> is included, packets matching the rule
              will have their HL (hop limit) incremented by
              <replaceable>number</replaceable>. Similarly, if <emphasis
              role="bold">-</emphasis> is included, matching packets have
              their HL decremented by <replaceable>number</replaceable>. If
              neither <emphasis role="bold">+</emphasis> nor <emphasis
              role="bold">-</emphasis> is given, the HL of matching packets is
              set to <replaceable>number</replaceable>. The valid range of
              values for <replaceable>number</replaceable> is 1-255.</para>
            </listitem>
          </orderedlist>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">SOURCE</emphasis> - {<emphasis
        role="bold">-</emphasis>|{<emphasis>interface</emphasis>|<emphasis
        role="bold">$FW</emphasis>}|[{<emphasis>interface</emphasis>|<emphasis
        role="bold">$FW</emphasis>}:]&lt;<emphasis>address-or-range</emphasis>[<emphasis
        role="bold">,</emphasis><emphasis>address-or-range</emphasis>]...}[<emphasis>exclusion</emphasis>]&gt;</term>

        <listitem>
          <para>Source of the packet. A comma-separated list of interface
          names, IP addresses, MAC addresses and/or subnets for packets being
          routed through a common path. List elements may also consist of an
          interface name followed by ":" and an address (e.g.,
          eth1:&lt;2002:ce7c:92b4::/48&gt;). For example, all packets for
          connections masqueraded to eth0 from other interfaces can be matched
          in a single rule with several alternative SOURCE criteria. However,
          a connection whose packets gets to eth0 in a different way, e.g.,
          direct from the firewall itself, needs a different rule.</para>

          <para>Accordingly, use $<emphasis role="bold">FW</emphasis> in its
          own separate rule for packets originating on the firewall. In such a
          rule, the MARK column may NOT specify either <emphasis
          role="bold">:P</emphasis> or <emphasis role="bold">:F</emphasis>
          because marking for firewall-originated packets always occurs in the
          OUTPUT chain.</para>

          <para>MAC addresses must be prefixed with "~" and use "-" as a
          separator.</para>

          <para>Example: ~00-A0-C9-15-39-78</para>

          <para>When an interface is not specified, the angled brackets
          ('&lt;' and '&gt;') surrounding the address(es) may be
          omitted.</para>

          <para>You may exclude certain hosts from the set already defined
          through use of an <emphasis>exclusion</emphasis> (see <ulink
          url="shorewall6-exclusion.html">shorewall6-exclusion</ulink>(5)).</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DEST</emphasis> - {<emphasis
        role="bold">-</emphasis>|{<emphasis>interface</emphasis>|$FW}[{<emphasis>interface</emphasis>|$FW}:]&lt;<emphasis>address-or-range</emphasis>[<emphasis
        role="bold">,</emphasis><emphasis>address-or-range</emphasis>]...}[<emphasis>exclusion</emphasis>]&gt;</term>

        <listitem>
          <para>Destination of the packet. Comma separated list of IP
          addresses and/or subnets. If your kernel and ip6tables include
          iprange match support, IP address ranges are also allowed. List
          elements may also consist of an interface name followed by ":" and
          an address (e.g., eth1:&lt;2002:ce7c:92b4::/48&gt;). If the
          <emphasis role="bold">MARK</emphasis> column specificies a
          classification of the form
          <emphasis>major</emphasis>:<emphasis>minor</emphasis> then this
          column may also contain an interface name.</para>

          <para>When an interface is not specified, the angled brackets
          ('&lt;' and '&gt;') surrounding the address(es) may be
          omitted.</para>

          <para>Beginning with Shorewall 4.4.13, $FW may be given by itself or
          qualified by an address list. This causes marking to occur in the
          INPUT chain.</para>

          <para>You may exclude certain hosts from the set already defined
          through use of an <emphasis>exclusion</emphasis> (see <ulink
          url="shorewall6-exclusion.html">shorewall6-exclusion</ulink>(5)).</para>
        </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>Protocol - <emphasis role="bold">ipp2p</emphasis> requires
          ipp2p match support in your kernel and ip6tables.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">PORT(S)</emphasis> (dport) - [<emphasis
        role="bold">-</emphasis>|<emphasis>port-name-number-or-range</emphasis>[<emphasis
        role="bold">,</emphasis><emphasis>port-name-number-or-range</emphasis>]...]</term>

        <listitem>
          <para>Optional destination Ports. A comma-separated list of Port
          names (from services(5)), <emphasis>port number</emphasis>s or
          <emphasis>port range</emphasis>s; if the protocol is <emphasis
          role="bold">ipv6-icmp</emphasis>, this column is interpreted as the
          destination icmp-type(s). ICMP types may be specified as a numeric
          type, a numberic type and code separated by a slash (e.g., 3/4), or
          a typename. See <ulink
          url="http://www.shorewall.net/configuration_file_basics.htm#ICMP">http://www.shorewall.net/configuration_file_basics.htm#ICMP</ulink>.</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>An entry in this field requires that the PROTO column specify
          tcp (6), udp (17), ipv6-icmp (58), sctp (132) or udplite (136). Use
          '-' if any of the following field is supplied.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">SOURCE PORT(S)</emphasis> (sport) -
        [<emphasis
        role="bold">-</emphasis>|<emphasis>port-name-number-or-range</emphasis>[<emphasis
        role="bold">,</emphasis><emphasis>port-name-number-or-range</emphasis>]...]</term>

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

          <para>An entry in this field requires that the PROTO column specify
          tcp (6), udp (17), sctp (132) or udplite (136). Use '-' if any of
          the following fields is supplied.</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>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>
          </variablelist>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>Optional. 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">LENGTH</emphasis> -
        [<emphasis>length</emphasis>|[<emphasis>min</emphasis>]<emphasis
        role="bold">:</emphasis>[<emphasis>max</emphasis>]]</term>

        <listitem>
          <para>Optional packet Length. This field, if present allow you to
          match the length of a packet against a specific value or range of
          values. You must have ip6tables length support for this to work. A
          range is specified in the form
          <emphasis>min</emphasis>:<emphasis>max</emphasis> where either
          <emphasis>min</emphasis> or <emphasis>max</emphasis> (but not both)
          may be omitted. If <emphasis>min</emphasis> is omitted, then 0 is
          assumed; if <emphasis>max</emphasis> is omitted, than any packet
          that is <emphasis>min</emphasis> or longer will match.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">TOS</emphasis> (Optional) -
        <emphasis>tos</emphasis></term>

        <listitem>
          <para>Type of service. Either a standard name, or a numeric value to
          match.</para>

          <programlisting>         <emphasis role="bold">Minimize-Delay</emphasis> (16)
         <emphasis role="bold">Maximize-Throughput</emphasis> (8)
         <emphasis role="bold">Maximize-Reliability</emphasis> (4)
         <emphasis role="bold">Minimize-Cost</emphasis> (2)
         <emphasis role="bold">Normal-Service</emphasis> (0)</programlisting>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">CONNBYTES</emphasis> -
        [!]<emphasis>min</emphasis>:[<emphasis>max</emphasis>[:{<emphasis
        role="bold">O</emphasis>|<emphasis role="bold">R</emphasis>|<emphasis
        role="bold">B</emphasis>}[:{<emphasis
        role="bold">B</emphasis>|<emphasis role="bold">P</emphasis>|<emphasis
        role="bold">A</emphasis>}]]]</term>

        <listitem>
          <para>Optional connection Bytes; defines a byte or packet range that
          the connection must fall within in order for the rule to
          match.</para>

          <para>A packet matches if the the packet/byte count is within the
          range defined by <emphasis>min</emphasis> and
          <emphasis>max</emphasis> (unless ! is given in which case, a packet
          matches if the packet/byte count is not within the range).
          <emphasis>min</emphasis> is an integer which defines the beginning
          of the byte/packet range. <emphasis>max</emphasis> is an integer
          which defines the end of the byte/packet range; if omitted, only the
          beginning of the range is checked. The first letter gives the
          direction which the range refers to:<blockquote>
              <para><emphasis role="bold">O</emphasis> - The original
              direction of the connection.</para>

              <para><emphasis role="bold">R</emphasis> - The opposite
              direction from the original connection.</para>

              <para><emphasis role="bold">B</emphasis> - The total of both
              directions.</para>
            </blockquote></para>

          <para>If omitted, <emphasis role="bold">B</emphasis> is
          assumed.</para>

          <para>The second letter determines what the range refers
          to.<blockquote>
              <para><emphasis role="bold">B</emphasis> - Bytes</para>

              <para><emphasis role="bold">P</emphasis> - Packets</para>

              <para><emphasis role="bold">A</emphasis> - Average packet
              size.</para>
            </blockquote>If omitted, <emphasis role="bold">B</emphasis> is
          assumed.</para>
        </listitem>
      </varlistentry>

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

        <listitem>
          <para>Optional. Names a Netfiler protocol
          <firstterm>helper</firstterm> module such as <option>ftp</option>,
          <option>sip</option>, <option>amanda</option>, etc. A packet will
          match if it was accepted by the named helper module. You can also
          append "-" and a port number to the helper module name (e.g.,
          <emphasis role="bold">ftp-21</emphasis>) to specify the port number
          that the original connection was made on.</para>

          <para>Example: Mark all FTP data connections with mark
          4:<programlisting>#MARK/    SOURCE    DEST      PROTO   PORT(S)    SOURCE  USER TEST LENGTH TOS CONNBYTES HELPER
#CLASSIFY                                        PORT(S)
4         ::/0      ::/0      TCP     -          -       -    -    -      -   -         ftp</programlisting></para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">HEADERS -
        [!][any:|exactly:]</emphasis><replaceable>header-list
        </replaceable>(Optional - Added in Shorewall 4.4.15)</term>

        <listitem>
          <para>The <replaceable>header-list</replaceable> consists of a
          comma-separated list of headers from the following list.</para>

          <variablelist>
            <varlistentry>
              <term><emphasis role="bold">auth</emphasis>, <emphasis
              role="bold">ah</emphasis>, or <emphasis
              role="bold">51</emphasis></term>

              <listitem>
                <para><firstterm>Authentication Headers</firstterm> extension
                header.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">esp</emphasis>, or <emphasis
              role="bold">50</emphasis></term>

              <listitem>
                <para><firstterm>Encrypted Security Payload</firstterm>
                extension header.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">hop</emphasis>, <emphasis
              role="bold">hop-by-hop</emphasis> or <emphasis
              role="bold">0</emphasis></term>

              <listitem>
                <para>Hop-by-hop options extension header.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">route</emphasis>, <emphasis
              role="bold">ipv6-route</emphasis> or <emphasis
              role="bold">41</emphasis></term>

              <listitem>
                <para>IPv6 Route extension header.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">frag</emphasis>, <emphasis
              role="bold">ipv6-frag</emphasis> or <emphasis
              role="bold">44</emphasis></term>

              <listitem>
                <para>IPv6 fragmentation extension header.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">none</emphasis>, <emphasis
              role="bold">ipv6-nonxt</emphasis> or <emphasis
              role="bold">59</emphasis></term>

              <listitem>
                <para>No next header</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">proto</emphasis>, <emphasis
              role="bold">protocol</emphasis> or <emphasis
              role="bold">255</emphasis></term>

              <listitem>
                <para>Any protocol header.</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>If <emphasis role="bold">any:</emphasis> is specified, the
          rule will match if any of the listed headers are present. If
          <emphasis role="bold">exactly:</emphasis> is specified, the will
          match packets that exactly include all specified headers. If neither
          is given, <emphasis role="bold">any:</emphasis> is assumed.</para>

          <para>If <emphasis role="bold">!</emphasis> is entered, the rule
          will match those packets which would not be matched when <emphasis
          role="bold">!</emphasis> is omitted.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Example</title>

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

        <listitem>
          <para>Mark all forwarded ICMP echo traffic with packet mark 1. Mark
          all forwarded peer to peer traffic with packet mark 4.</para>

          <para>This is a little more complex than otherwise expected. Since
          the ipp2p module is unable to determine all packets in a connection
          are P2P packets, we mark the entire connection as P2P if any of the
          packets are determined to match.</para>

          <para>We assume packet/connection mark 0 means unclassified.</para>

          <programlisting>       #MARK/    SOURCE    DEST         PROTO   PORT(S)       SOURCE  USER    TEST
       #CLASSIFY                                              PORT(S)
       1         ::/0      ::/0         icmp    echo-request
       1         ::/0      ::/0         icmp    echo-reply
       RESTORE   ::/0      ::/0         all     -             -       -       0
       CONTINUE  ::/0      ::/0         all     -             -       -      !0
       4         ::/0      ::/0         ipp2p:all
       SAVE      ::/0      ::/0         all     -             -       -       !0</programlisting>

          <para>If a packet hasn't been classifed (packet mark is 0), copy the
          connection mark to the packet mark. If the packet mark is set, we're
          done. If the packet is P2P, set the packet mark to 4. If the packet
          mark has been set, save it to the connection mark.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>FILES</title>

    <para>/etc/shorewall6/tcrules</para>
  </refsect1>

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

    <para><ulink
    url="http://shorewall.net/traffic_shaping.htm">http://shorewall.net/traffic_shaping.htm</ulink></para>

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

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

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

    <para>shorewall6(8), shorewall6-accounting(5), shorewall6-actions(5),
    shorewall6-blacklist(5), shorewall6-ecn(5), shorewall6-exclusion(5),
    shorewall6-hosts(5), shorewall6-interfaces(5), shorewall6-maclist(5),
    shoewall6-netmap(5),shorewall6-params(5), shorewall6-policy(5),
    shorewall6-providers(5), shorewall6-route_rules(5),
    shorewall6-routestopped(5), shorewall6-rules(5), shorewall6.conf(5),
    shorewall6-secmarks(5), shorewall6-tcclasses(5), shorewall6-tcdevices(5),
    shorewall6-tos(5), shorewall6-tunnels(5), shorewall6-zones(5)</para>
  </refsect1>
</refentry>