shorewall_code/manpages/shorewall-rules.xml

<?xml version="1.0" encoding="UTF-8"?>
<refentry>
  <refmeta>
    <refentrytitle>shorewall-rules</refentrytitle>

    <manvolnum>5</manvolnum>
  </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>Rules in this file govern connection establishment. 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 QUEUE rules.</para>

    <para>In most places where an IP address or subnet is allowed, you can
    preceed the address/subnet with "!" (e.g., !192.168.1.0/24) to indicate
    that the rule matches all addresses except the address/subnet given.
    Notice that no white space is permitted between "!" and the
    address/subnet.</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">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 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 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">NEW</emphasis></term>

        <listitem>
          <para>Packets in the NEW and INVALID states are processed by rules
          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 I suggest 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 shorewall.conf(5) then the
      <emphasis role="bold">ESTABLISHED</emphasis> and <emphasis
      role="bold">RELATED</emphasis> sections must be empty.</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>The columns in the file are as follows.</para>

    <variablelist>
      <varlistentry>
        <term><emphasis role="bold">ACTION</emphasis> — {<emphasis
        role="bold">ACCEPT</emphasis>[<emphasis
        role="bold">+</emphasis>]|<emphasis
        role="bold">NONAT</emphasis>|<emphasis
        role="bold">DROP</emphasis>|<emphasis
        role="bold">REJECT</emphasis>|<emphasis
        role="bold">DNAT</emphasis>[<emphasis
        role="bold">-</emphasis>]|<emphasis
        role="bold">SAME</emphasis>[<emphasis
        role="bold">-</emphasis>]|<emphasis
        role="bold">REDIRECT</emphasis>[<emphasis
        role="bold">-</emphasis>]|<emphasis
        role="bold">CONTINUE</emphasis>|<emphasis
        role="bold">LOG</emphasis>|<emphasis
        role="bold">QUEUE</emphasis>|<emphasis
        role="bold">COMMENT</emphasis>|<emphasis>action</emphasis>|<emphasis>macro</emphasis>[<emphasis
        role="bold">/</emphasis><emphasis>target</emphasis>}<emphasis
        role="bold">[:</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. 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">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">DROP</emphasis></term>

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

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

              <listitem>
                <para>disallow the request and return an icmp-unreachable or
                an RST packet.</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">SAME</emphasis></term>

              <listitem>
                <para>Similar to <emphasis role="bold">DNAT</emphasis> except
                that the port may not be remapped and when multiple server
                addresses are listed, all requests from a given remote system
                go to the same server.</para>
              </listitem>
            </varlistentry>

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

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

                <para>Like SAME but only generates the nat iptables rule and
                not the companion <emphasis role="bold">ACCEPT</emphasis>
                rule.</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">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
                shorewall-zones(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).</para>
              </listitem>
            </varlistentry>

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

              <listitem>
                <para>Simply log the packet and continue with the next
                rule.</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">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>action</emphasis></term>

              <listitem>
                <para>The name of an <emphasis>action</emphasis> defined in
                shorewall-actions(5) or in
                /usr/share/shorewall/actions.std.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis>macro</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 "/" and the
                <emphasis>target</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>

                <programlisting></programlisting>
              </listitem>
            </varlistentry>
          </variablelist>

          <blockquote>
            <para>The <emphasis role="bold">ACTION</emphasis> may optionally
            be followed by ":" and a syslog log level (e.g, REJECT:info or
            DNAT: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,
            SAME, 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> defined in shorewall-actions(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>
            (must be in upper case) as a log level.This will log to the ULOG
            target for routing to a separate log through use of ulogd
            (http://www.gnumonks.org/projects/ulogd).</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 shorewall.conf(5)).</para>

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

      <varlistentry>
        <term><emphasis role="bold">SOURCE</emphasis> —
        {<emphasis>zone</emphasis>|<emphasis
        role="bold">all</emphasis>[<emphasis
        role="bold">+</emphasis>][<emphasis
        role="bold">-</emphasis>]}<emphasis
        role="bold">[:</emphasis><emphasis>interface</emphasis>][<emphasis
        role="bold">:</emphasis>{<emphasis>address-or-range</emphasis>[,<emphasis>address-or-range</emphasis>]...[<emphasis>exclusion</emphasis>]|<emphasis>exclusion</emphasis>|<emphasis
        role="bold">+</emphasis><emphasis>ipset</emphasis>}</term>

        <listitem>
          <para>Source hosts to which the rule applies. May be a zone defined
          in /etc/shorewall/zones, <emphasis role="bold">$FW</emphasis> to
          indicate the firewall itself, <emphasis role="bold">all</emphasis>,
          <emphasis role="bold">all+</emphasis>, <emphasis
          role="bold">all-</emphasis>, <emphasis role="bold">all+-</emphasis>
          or <emphasis role="bold">none</emphasis>.</para>

          <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>

          <para><emphasis role="bold">all</emphasis> means "All Zones",
          including the firewall itself. <emphasis role="bold">all-</emphasis>
          means "All Zones, except the firewall itself". When <emphasis
          role="bold">all</emphasis>[<emphasis role="bold">-</emphasis>] is
          used either in the <emphasis role="bold">SOURCE</emphasis> or
          <emphasis role="bold">DEST</emphasis> column intra-zone traffic is
          not affected. When <emphasis role="bold">all+</emphasis>[<emphasis
          role="bold">-</emphasis>] is "used, intra-zone traffic is
          affected.</para>

          <para>Except when <emphasis role="bold">all</emphasis>[<emphasis
          role="bold">+</emphasis>][<emphasis role="bold">-</emphasis>] is
          specified, clients may be further restricted to a list of networks
          and/or hosts by appending ":" and a comma-separated list of network
          and/or host addresses. Hosts may be specified by IP or MAC address;
          mac addresses must begin with "~" and must use "-" as a
          separator.</para>

          <para>Hosts may also be specified as an IP address range using the
          syntax
          <emphasis>lowaddress</emphasis>-<emphasis>highaddress</emphasis>.
          This requires that your kernel and iptables contain iprange match
          support. If your kernel and iptables have ipset match support then
          you may give the name of an ipset prefaced by "+". The ipset name
          may be optionally followed by a number from 1 to 6 enclosed in
          square brackets ([]) to indicate the number of levels of source
          bindings to be matched.</para>

          <para>You may exclude certain hosts from the set already defined
          through use of an <emphasis>exclusion</emphasis> (see
          shorewall-exclusion(5)).</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>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>
          </variablelist>

          <blockquote>
            <para>Alternatively, clients may be specified by interface by
            appending ":" to the zone name followed by the interface name. For
            example, <emphasis role="bold">loc:eth1</emphasis> specifies a
            client that communicates with the firewall system through eth1.
            This may be optionally followed by another colon (":") and an
            IP/MAC/subnet address as described above (e.g., <emphasis
            role="bold">loc:eth1:192.168.1.5</emphasis>).</para>
          </blockquote>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DEST</emphasis> —
        {<emphasis>zone</emphasis>|<emphasis
        role="bold">all</emphasis>[<emphasis
        role="bold">+</emphasis>][<emphasis
        role="bold">-</emphasis>]}<emphasis
        role="bold">[:{</emphasis><emphasis>interface</emphasis>|<emphasis>address-or-range</emphasis>[,<emphasis>address-or-range</emphasis>]...[<emphasis>exclusion</emphasis>]|<emphasis>exclusion</emphasis>|<emphasis
        role="bold">+</emphasis><emphasis>ipset</emphasis>}]</term>

        <listitem>
          <para>Location of Server. May be a zone defined in
          shorewall-zones(5), $<emphasis role="bold">FW</emphasis> to indicate
          the firewall itself, <emphasis role="bold">all</emphasis>. <emphasis
          role="bold">all+</emphasis> or <emphasis
          role="bold">none</emphasis>.</para>

          <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>

          <para>When <emphasis role="bold">all</emphasis> is used either in
          the <emphasis role="bold">SOURCE</emphasis> or <emphasis
          role="bold">DEST</emphasis> column intra-zone traffic is not
          affected. When <emphasis role="bold">all+</emphasis> is used,
          intra-zone traffic is affected.</para>

          <para>Except when <emphasis role="bold">all</emphasis>[<emphasis
          role="bold">+</emphasis>] is specified, the server may be further
          restricted to a particular network, host or interface by appending
          ":" and the network, host or interface. See <emphasis
          role="bold">SOURCE</emphasis> above.</para>

          <para>You may exclude certain hosts from the set already defined
          through use of an <emphasis>exclusion</emphasis> (see
          shorewall-exclusion(5)).</para>

          <para>Restrictions:</para>

          <para>1. MAC addresses are not allowed (this is a Netfilter
          restriction).</para>

          <para>2. In <emphasis role="bold">DNAT</emphasis> rules, only IP
          addresses are allowed; no FQDNs or subnet addresses are
          permitted.</para>

          <para>3. You may not specify both an interface and an
          address.</para>

          <para>Like in the <emphasis role="bold">SOURCE</emphasis> column,
          you may specify a range of IP addresses using the syntax
          <emphasis>lowaddress</emphasis>-<emphasis>highaddress</emphasis>.
          When the <emphasis role="bold">ACTION</emphasis> is <emphasis
          role="bold">DNAT</emphasis> or <emphasis
          role="bold">DNAT-</emphasis>, the connections will be assigned to
          addresses in the range in a round-robin fashion.</para>

          <para>If you kernel and iptables have ipset match support then you
          may give the name of an ipset prefaced by "+". The ipset name may be
          optionally followed by a number from 1 to 6 enclosed in square
          brackets ([]) to indicate the number of levels of destination
          bindings to be matched. Only one of the <emphasis
          role="bold">SOURCE</emphasis> and <emphasis
          role="bold">DEST</emphasis> columns may specify an ipset
          name.</para>

          <para>The port that the server is listening on may be included and
          separated from the server's IP address by ":". If omitted, the
          firewall will not modifiy the destination port. A destination port
          may only be included if the <emphasis role="bold">ACTION</emphasis>
          is <emphasis role="bold">DNAT</emphasis> or <emphasis
          role="bold">REDIRECT</emphasis>. Example:</para>

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

              <listitem>
                <para><emphasis role="bold">loc:192.168.1.3:3128</emphasis>
                specifies a local server at IP address 192.168.1.3 and
                listening on port 3128. The port number MUST be specified as
                an integer and not as a name from services(5).</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <blockquote>
            <para>if the <emphasis role="bold">ACTION</emphasis> is <emphasis
            role="bold">REDIRECT</emphasis> or <emphasis
            role="bold">REDIRECT-</emphasis>, this column needs only to
            contain the port number on the firewall that the request should be
            redirected to.</para>
          </blockquote>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">PROTO</emphasis> (Optional) — {<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 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.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DEST PORT(S) </emphasis>(Optional) —
        {<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>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).</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">CLIENT PORT(S)</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 multiport match support.</para>

          <para>Otherwise, a separate rule will be generated for each
          port.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">SOURCE PORT(S)</emphasis> (Optional) —
        {<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>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>

          <warning>
            <para>Unless you really understand TCP/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>

          <blockquote>
            <para>If you don't want to restrict client ports but need to
            specify an <emphasis role="bold">ORIGINAL DEST</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">DEST PORT(S)</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 multiport match support.</para>

            <para>Otherwise, a separate rule will be generated for each
            port.</para>
          </blockquote>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">ORIGINAL DEST</emphasis> (Optional) —
        [<emphasis
        role="bold">-</emphasis>|<emphasis>address</emphasis>[,<emphasis>address</emphasis>]...[<emphasis>exclusion</emphasis>]|<emphasis>exclusion</emphasis>]</term>

        <listitem>
          <para>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">SERVER</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>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.</para>

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

      <varlistentry>
        <term><emphasis role="bold">RATE LIMIT</emphasis> (Optional) —
        [<emphasis role="bold">-</emphasis>|<emphasis>rate</emphasis><emphasis
        role="bold">/</emphasis>{<emphasis
        role="bold">sec</emphasis>|<emphasis
        role="bold">min</emphasis>}[:<emphasis>burst</emphasis>]</term>

        <listitem>
          <para>You may 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 whitespace embedded in
          the specification.</para>

          <para>Example: <emphasis role="bold">10/sec:20</emphasis></para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">USER/GROUP</emphasis> (Optional) —
        [<emphasis
        role="bold">!</emphasis>][<emphasis>user-name-or-number</emphasis>][<emphasis
        role="bold">:</emphasis><emphasis>group-name-or-number</emphasis>][<emphasis
        role="bold">+</emphasis><emphasis>program-name</emphasis>]</term>

        <listitem>
          <para>This 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>

            <varlistentry>
              <term>+upnpd</term>

              <listitem>
                <para>#program named upnpd</para>

                <important>
                  <para>The ability to specify a program name was removed from
                  Netfilter in kernel version 2.6.14.</para>
                </important>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Example</title>

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

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

          <programlisting>         #ACTION SOURCE  DEST PROTO      DEST    SOURCE  ORIGINAL
         #                               PORT    PORT(S) DEST
         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   DEST    SOURCE  ORIGINAL
        #                                       PORT    PORT(S) DEST
        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  DEST  SOURCE  ORIGINAL RATE
        #                                     PORT  PORT(S) DEST     LIMIT
        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 DEST    SOURCE  ORIGINAL
        #                               PORT    PORT(S) DEST
        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   DEST    SOURCE  ORIGINAL
        #                                       PORT    PORT(S) DEST
        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   DEST    SOURCE  ORIGINAL
        #                                       PORT    PORT(S) DEST
        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   DEST    SOURCE  ORIGINAL
        #                                           PORT    PORT(S) DEST
        ACCEPT   net    loc:192.168.1.3:22  tcp     2222</programlisting>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>FILES</title>

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

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

    <para><ulink
    url="http://shorewall.net/Documentation.htm#Rules">http://shorewall.net/Documentation.htm#Rules</ulink></para>

    <para>shorewall(8), shorewall-accounting(5), shorewall-actions(5),
    shorewall-blacklist(5), shorewall-hosts(5), shorewall-interfaces(5),
    shorewall-ipsec(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-route_routes(5), shorewall-routestopped(5), shorewall.conf(5),
    shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5),
    shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)</para>
  </refsect1>
</refentry>