shorewall_code/manpages/shorewall.conf.xml

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

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

  <refnamediv>
    <refname>shorewall.conf</refname>

    <refpurpose>Shorewall global configuration file</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>/etc/shorewall/shorewall.conf</command>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>This file sets options that apply to Shorewall as a whole.</para>

    <para>The file consists of Shell comments (lines beginning with '#'),
    blank lines and assignment statements
    (<emphasis>variable</emphasis>=<emphasis>value</emphasis>).</para>
  </refsect1>

  <refsect1>
    <title>OPTIONS</title>

    <para>Many options have as their value a <emphasis>log-level</emphasis>.
    Log levels are a method of describing to syslog (8) the importance of a
    message and a number of parameters in this file have log levels as their
    value.</para>

    <para>These levels are defined by syslog and are used to determine the
    destination of the messages through entries in /etc/syslog.conf (5). The
    syslog documentation refers to these as "priorities"; Netfilter calls them
    "levels" and Shorewall also uses that term.</para>

    <para>Valid levels are:</para>

    <programlisting>       7       debug
       6       info
       5       notice
       4       warning
       3       err
       2       crit
       1       alert
       0       emerg</programlisting>

    <para>For most Shorewall logging, a level of 6 (info) is appropriate.
    Shorewall log messages are generated by NetFilter and are logged using
    facility 'kern' and the level that you specifify. If you are unsure of the
    level to choose, 6 (info) is a safe bet. You may specify levels by name or
    by number.</para>

    <para>If you have built your kernel with ULOG target support, you may also
    specify a log level of ULOG (must be all caps). Rather than log its
    messages to syslogd, Shorewall will direct netfilter to log the messages
    via the ULOG target which will send them to a process called 'ulogd'.
    ulogd is available with most Linux distributions (although it probably
    isn't installed by default). Ulogd is also available from <ulink
    url="http://www.netfilter.org/projects/ulogd/index.html">http://www.netfilter.org/projects/ulogd/index.html</ulink>
    and can be configured to log all Shorewall message to their own log
    file</para>

    <para>The following options may be set in shorewall.conf.</para>

    <variablelist>
      <varlistentry>
        <term><emphasis
        role="bold">ACCEPT_DEFAULT=</emphasis>{<emphasis>action</emphasis>|<emphasis>macro</emphasis>|<emphasis
        role="bold">none</emphasis>}</term>

        <listitem>
          <para></para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">DROP_DEFAULT=</emphasis>{<emphasis>action</emphasis>|<emphasis>macro</emphasis>|<emphasis
        role="bold">none</emphasis>}</term>

        <listitem>
          <para></para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">REJECT_DEFAULT=</emphasis>{<emphasis>action</emphasis>|<emphasis>macro</emphasis>|<emphasis
        role="bold">none</emphasis>}</term>

        <listitem>
          <para></para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">QUEUE_DEFAULT=</emphasis>{<emphasis>action</emphasis>|<emphasis>macro</emphasis>|<emphasis
        role="bold">none</emphasis>}</term>

        <listitem>
          <para>In earlier Shorewall versions, a "default action" for DROP and
          REJECT policies was specified in the file
          /usr/share/shorewall/actions.std.</para>

          <para>To allow for default rules to be applied when USE_ACTIONS=No,
          the DROP_DEFAULT, REJECT_DEFAULT, ACCEPT_DEFAULT and QUEUE_DEFAULT
          options have been added.</para>

          <para>DROP_DEFAULT describes the rules to be applied before a
          connection request is dropped by a DROP policy; REJECT_DEFAULT
          describes the rules to be applied if a connection request is
          rejected by a REJECT policy. The other two are similar for ACCEPT
          and QUEUE policies.</para>

          <para>The value applied to these may be:</para>

          <simplelist>
            <member>a) The name of an
            <replaceable>action</replaceable>.</member>

            <member>b) The name of a <replaceable>macro</replaceable></member>

            <member>c) <emphasis role="bold">None</emphasis> or <emphasis
            role="bold">none</emphasis></member>
          </simplelist>

          <para>The default values are:</para>

          <simplelist>
            <member>DROP_DEFAULT="Drop"</member>

            <member>REJECT_DEFAULT="Reject"</member>

            <member>ACCEPT_DEFAULT="none"</member>

            <member>QUEUE_DEFAULT="none"</member>
          </simplelist>

          <para>If USE_ACTIONS=Yes, then these values refer to action.Drop and
          action.Reject respectively. If USE_ACTIONS=No, then these values
          refer to macro.Drop and macro.Reject.</para>

          <para>If you set the value of either option to "None" then no
          default action will be used and the default action or macro must be
          specified in <ulink
          url="shorewall-policy.html">shorewall-policy</ulink>(5).</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">ADD_IP_ALIASES=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>This parameter determines whether Shorewall automatically adds
          the external address(es) in <ulink
          url="shorewall-nat.html">shorewall-nat</ulink>(5). If the variable
          is set to <emphasis role="bold">Yes</emphasis> or <emphasis
          role="bold">yes</emphasis> then Shorewall automatically adds these
          aliases. If it is set to <emphasis role="bold">No</emphasis> or
          <emphasis role="bold">no</emphasis>, you must add these aliases
          yourself using your distribution's network configuration
          tools.</para>

          <para>If this variable is not set or is given an empty value
          (ADD_IP_ALIASES="") then ADD_IP_ALIASES=Yes is assumed.</para>

          <warning>
            <para>Addresses added by ADD_IP_ALIASES=Yes are deleted and
            re-added during shorewall restart. As a consequence, connections
            using those addresses may be severed.</para>
          </warning>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">ADD_SNAT_ALIASES=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>This parameter determines whether Shorewall automatically adds
          the SNAT ADDRESS in <ulink
          url="shorewall-masq.html">shorewall-masq</ulink>(5). If the variable
          is set to <emphasis role="bold">Yes</emphasis> or <emphasis
          role="bold">yes</emphasis> then Shorewall automatically adds these
          addresses. If it is set to <emphasis role="bold">No</emphasis> or
          <emphasis role="bold">no</emphasis>, you must add these addresses
          yourself using your distribution's network configuration
          tools.</para>

          <para>If this variable is not set or is given an empty value
          (ADD_SNAT_ALIASES="") then ADD_SNAT_ALIASES=No is assumed.</para>

          <warning>
            <para>Addresses added by ADD_SNAT_ALIASES=Yes are deleted and
            re-added during shorewall restart. As a consequence, connections
            using those addresses may be severed.</para>
          </warning>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">ADMINISABSENTMINDED=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>The value of this variable affects Shorewall's stopped state.
          When ADMINISABSENTMINDED=No, only traffic to/from those addresses
          listed in <ulink
          url="shorewall-routestopped.html">shorewall-routestopped</ulink>(5)
          is accepted when Shorewall is stopped. When ADMINISABSENTMINDED=Yes,
          in addition to traffic to/from addresses in <ulink
          url="shorewall-routestopped.html">shorewall-routestopped</ulink>(5),
          connections that were active when Shorewall stopped continue to work
          and all new connections from the firewall system itself are allowed.
          If this variable is not set or is given the empty value then
          ADMINISABSENTMINDED=No is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">BLACKLIST_DISPOSITION=</emphasis>[<emphasis
        role="bold">DROP</emphasis>|<emphasis
        role="bold">REJECT</emphasis>]</term>

        <listitem>
          <para>This parameter determines the disposition of packets from
          blacklisted hosts. It may have the value DROP if the packets are to
          be dropped or REJECT if the packets are to be replied with an ICMP
          port unreachable reply or a TCP RST (tcp only). If you do not assign
          a value or if you assign an empty value then DROP is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">BLACKLIST_LOGLEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>

        <listitem>
          <para>This parameter determines if packets from blacklisted hosts
          are logged and it determines the syslog level that they are to be
          logged at. Its value is a syslog level (Example:
          BLACKLIST_LOGLEVEL=debug). If you do not assign a value or if you
          assign an empty value then packets from blacklisted hosts are not
          logged.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">BRIDGING=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>When set to <emphasis role="bold">Yes</emphasis> or <emphasis
          role="bold">yes</emphasis>, enables Shorewall Bridging
          support.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">CLAMPMSS=[</emphasis><emphasis
        role="bold">Yes</emphasis>|<emphasis
        role="bold">No</emphasis>|<emphasis>value</emphasis>]</term>

        <listitem>
          <para>This parameter enables the TCP Clamp MSS to PMTU feature of
          Netfilter and is usually required when your internet connection is
          through PPPoE or PPTP. If set to <emphasis
          role="bold">Yes</emphasis> or <emphasis role="bold">yes</emphasis>,
          the feature is enabled. If left blank or set to <emphasis
          role="bold">No</emphasis> or <emphasis role="bold">no</emphasis>,
          the feature is not enabled.</para>

          <note>
            <para>This option requires CONFIG_IP_NF_TARGET_TCPMSS in your
            kernel.</para>
          </note>

          <para>You may also set CLAMPMSS to a numeric
          <emphasis>value</emphasis> (e.g., CLAMPMSS=1400). This will set the
          MSS field in TCP SYN packets going through the firewall to the
          <emphasis>value</emphasis> that you specify.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">CLEAR_TC=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>If this option is set to <emphasis role="bold">No</emphasis>
          then Shorewall won't clear the current traffic control rules during
          [re]start. This setting is intended for use by people that prefer to
          configure traffic shaping when the network interfaces come up rather
          than when the firewall is started. If that is what you want to do,
          set TC_ENABLED=Yes and CLEAR_TC=No and do not supply an
          /etc/shorewall/tcstart file. That way, your traffic shaping rules
          can still use the “fwmark” classifier based on packet marking
          defined in <ulink
          url="shorewall-tcrules.html">shorewall-tcrules</ulink>(5). If not
          specified, CLEAR_TC=Yes is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">CONFIG_PATH</emphasis>=[<emphasis>directory</emphasis>[:<emphasis>directory</emphasis>]...]</term>

        <listitem>
          <para>Specifies where configuration files other than shorewall.conf
          may be found. CONFIG_PATH is specifies as a list of directory names
          separated by colons (":"). When looking for a configuration file
          other than shorewall.conf:</para>

          <itemizedlist>
            <listitem>
              <para>If the command is "try" or if "-c &lt;configuration
              directory&gt;" was specified in the command then the directory
              given in the command is searched first.</para>
            </listitem>

            <listitem>
              <para>Next, each directory in the CONFIG_PATH setting is
              searched in sequence.</para>
            </listitem>
          </itemizedlist>

          <para>If CONFIG_PATH is not given or if it is set to the empty value
          then the contents of /usr/share/shorewall/configpath are used. As
          released from shorewall.net, that file sets the CONFIG_PATH to
          /etc/shorewall:/usr/share/shorewall but your particular distribution
          may set it differently. See the output of shorewall show config for
          the default on your system.</para>

          <para>Note that the setting in /usr/share/shorewall/configpath is
          always used to locate shorewall.conf.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DELAYBLACKLISTLOAD=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>Users with a large static black list (<ulink
          url="shorewall-blacklist.html">shorewall-blacklist</ulink>(5)) may
          want to set the DELAYBLACKLISTLOAD option to <emphasis
          role="bold">Yes</emphasis>. When DELAYBLACKLISTLOAD=Yes, Shorewall
          will enable new connections before loading the blacklist rules.
          While this may allow connections from blacklisted hosts to slip by
          during construction of the blacklist, it can substantially reduce
          the time that all new connections are disabled during <emphasis
          role="bold">shorewall</emphasis> [<emphasis
          role="bold">re</emphasis>]<emphasis
          role="bold">start</emphasis>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DETECT_DNAT_ADDRS=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>If set to <emphasis role="bold">Yes</emphasis> or <emphasis
          role="bold">yes</emphasis>, Shorewall will detect the first IP
          address of the interface to the source zone and will include this
          address in DNAT rules as the original destination IP address. If set
          to <emphasis role="bold">No</emphasis> or <emphasis
          role="bold">no</emphasis>, Shorewall will not detect this address
          and any destination IP address will match the DNAT rule. If not
          specified or empty, “DETECT_DNAT_ADDRS=Yes” is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">DYNAMIC_ZONES=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>When set to <emphasis role="bold">Yes</emphasis> or <emphasis
          role="bold">yes</emphasis>, enables dynamic zones. DYNAMIC_ZONES=Yes
          is not allowed in configurations that will run under Shorewall
          Lite.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">EXPORTPARAMS=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>It is quite difficult to code a 'params' file that assigns
          other than constant values such that it works correctly with
          Shorewall Lite. The EXPORTPARAMS option works around this problem.
          When EXPORTPARAMS=No, the 'params' file is not copied to the
          compiler output.</para>

          <para>With EXPORTPARAMS=No, if you need to set environmental
          variables on the firewall system for use by your extension scripts,
          then do so in the init extension script.</para>

          <para>The default is EXPORTPARAMS=Yes</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">FASTACCEPT=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>Normally, Shorewall accepting ESTABLISHED/RELATED packets
          until these packets reach the chain in which the original connection
          was accepted. So for packets going from the 'loc' zone to the 'net'
          zone, ESTABLISHED/RELATED packets are ACCEPTED in the 'loc2net'
          chain.</para>

          <para>If you set FASTACCEPT=Yes, then ESTABLISHED/RELEATED packets
          are accepted early in the INPUT, FORWARD and OUTPUT chains. If you
          set FASTACCEPT=Yes then you may not include rules in the ESTABLISHED
          or RELATED sections of <ulink
          url="shorewall-rules.html">shorewall-rules</ulink>(5).</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">HIGH_ROUTE_MARKS=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>Prior to version 3.2.0, it was not possible to use connection
          marking in <ulink
          url="shorewall-tcrules.html">shorewall-tcrules</ulink>(5) if you
          have a multi-ISP configuration that uses the track option.</para>

          <para>Beginning with release 3.2.0, you may now set
          HIGH_ROUTE_MARKS=Yes in to effectively divide the packet mark and
          connection mark into two 8-byte mark fields.</para>

          <para>When you do this:</para>

          <orderedlist numeration="loweralpha">
            <listitem>
              <para>The MARK field in the providers file must have a value
              that is less than 65536 and that is a multiple of 256 (using hex
              representation, the values are 0x0100-0xFF00 with the low-order
              8 bits being zero).</para>
            </listitem>

            <listitem>
              <para>You may only set those mark values in the PREROUTING
              chain.</para>
            </listitem>

            <listitem>
              <para>Marks used for traffic shaping must still be in the range
              of 1-255 and may still not be set in the PREROUTING
              chain.</para>
            </listitem>

            <listitem>
              <para>When you SAVE or RESTORE in tcrules, only the TC mark
              value is saved or restored. Shorewall handles saving and
              restoring the routing (provider) marks.</para>
            </listitem>
          </orderedlist>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">IMPLICIT_CONTINUE=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>When this option is set to <emphasis
          role="bold">Yes</emphasis>, it causes subzones to be treated
          differently with respect to policies.</para>

          <para>Subzones are defined by following their name with ":" and a
          list of parent zones (in <ulink
          url="shorewall-zones.html">shorewall-zones</ulink>(5)). Normally,
          you want to have a set of special rules for the subzone and if a
          connection doesn't match any of those subzone-specific rules then
          you want the parent zone rules and policies to be applied; see
          <ulink url="shorewall-nesting.html">shorewall-nesting</ulink>(5).
          With IMPLICIT_CONTINUE=Yes, that happens automatically.</para>

          <para>If IMPLICIT_CONTINUE=No or if IMPLICIT_CONTINUE is not set,
          then subzones are not subject to this special treatment. With
          IMPLICIT_CONTINUE=Yes, an implicit CONTINUE policy may be overridden
          by including an explicit policy (one that does not specify "all" in
          either the SOURCE or the DEST columns).</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">IP_FORWARDING=</emphasis>[<emphasis
        role="bold">On</emphasis>|<emphasis
        role="bold">Off</emphasis>|<emphasis
        role="bold">Keep</emphasis>]</term>

        <listitem>
          <para>This parameter determines whether Shorewall enables or
          disables IPV4 Packet Forwarding (/proc/sys/net/ipv4/ip_forward).
          Possible values are:</para>

          <variablelist>
            <varlistentry>
              <term><emphasis role="bold">On</emphasis> or <emphasis
              role="bold">on</emphasis></term>

              <listitem>
                <para>packet forwarding will be enabled.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">Off</emphasis> or <emphasis
              role="bold">off</emphasis></term>

              <listitem>
                <para>packet forwarding will be disabled.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term><emphasis role="bold">Keep</emphasis> or <emphasis
              role="bold">keep</emphasis></term>

              <listitem>
                <para>Shorewall will neither enable nor disable packet
                forwarding.</para>
              </listitem>
            </varlistentry>
          </variablelist>

          <para>If this variable is not set or is given an empty value
          (IP_FORWARD="") then IP_FORWARD=On is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">IPSECFILE=</emphasis>{<emphasis
        role="bold">zones</emphasis>|<emphasis
        role="bold">ipsec</emphasis>}</term>

        <listitem>
          <para>This should be set to <emphasis role="bold">zones</emphasis>
          for all new Shorewall installations. IPSECFILE=ipsec is only used
          for compatibility with pre-Shorewall-3.0 configurations.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">IPTABLES=</emphasis>[<emphasis>pathname</emphasis>]</term>

        <listitem>
          <para>This parameter names the iptables executable to be used by
          Shorewall. If not specified or if specified as a null value, then
          the iptables executable located using the PATH option is
          used.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">LOG_MARTIANS=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>If set to <emphasis role="bold">Yes</emphasis> or <emphasis
          role="bold">yes</emphasis>, sets
          /proc/sys/net/ipv4/conf/all/log_martians and
          /proc/sys/net/ipv4/conf/default/log_martians to 1. Default is
          <emphasis role="bold">No</emphasis> which sets both of the above to
          zero. If you do not enable martian logging for all interfaces, you
          may still enable it for individual interfaces using the <emphasis
          role="bold">logmartians</emphasis> interface option in <ulink
          url="shorewall-interfaces.html">shorewall-interfaces</ulink>(5).</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">LOGALLNEW=</emphasis>[<emphasis>log-level</emphasis>]</term>

        <listitem>
          <para>When set to a log level, this option causes Shorewall to
          generate a logging rule as the first rule in each builtin
          chain.</para>

          <itemizedlist>
            <listitem>
              <para>The table name is used as the chain name in the log
              prefix.</para>
            </listitem>

            <listitem>
              <para>The chain name is used as the target in the log
              prefix.</para>
            </listitem>
          </itemizedlist>

          <para>For example, using the default LOGFORMAT, the log prefix for
          logging from the nat table's PREROUTING chain is:</para>

          <programlisting>    Shorewall:nat:PREROUTING
 </programlisting>

          <important>
            <para>There is no rate limiting on these logging rules so use
            LOGALLNEW at your own risk; it may cause high CPU and disk
            utilization and you may not be able to control your firewall after
            you enable this option.</para>
          </important>

          <caution>
            <para>Do not use this option if the resulting log messages will be
            sent to another system.</para>
          </caution>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">LOGFILE=</emphasis>[<emphasis>pathname</emphasis>]</term>

        <listitem>
          <para>This parameter tells the /sbin/shorewall program where to look
          for Shorewall messages when processing the <emphasis
          role="bold">dump</emphasis>, <emphasis
          role="bold">logwatch</emphasis>, <emphasis role="bold">show
          log</emphasis>, and <emphasis role="bold">hits</emphasis> commands.
          If not assigned or if assigned an empty value, /var/log/messages is
          assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">LOGFORMAT=</emphasis>[<emphasis
        role="bold">"</emphasis><emphasis>formattemplate</emphasis><emphasis
        role="bold">"</emphasis>]</term>

        <listitem>
          <para>The value of this variable generate the --log-prefix setting
          for Shorewall logging rules. It contains a “printf” formatting
          template which accepts three arguments (the chain name, logging rule
          number (optional) and the disposition). To use LOGFORMAT with
          fireparse, set it as:</para>

          <programlisting>    LOGFORMAT="fp=%s:%d a=%s "</programlisting>

          <para>If the LOGFORMAT value contains the substring “%d” then the
          logging rule number is calculated and formatted in that position; if
          that substring is not included then the rule number is not included.
          If not supplied or supplied as empty (LOGFORMAT="") then
          “Shorewall:%s:%s:” is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">LOGBURST=</emphasis>[<emphasis>burst</emphasis>]</term>

        <listitem>
          <para></para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">LOGRATE=</emphasis>[<emphasis>rate</emphasis>/{<emphasis
        role="bold">minute</emphasis>|<emphasis
        role="bold">second</emphasis>}]</term>

        <listitem>
          <para>These parameters set the match rate and initial burst size for
          logged packets. Please see iptables(8) for a description of the
          behavior of these parameters (the iptables option --limit is set by
          LOGRATE and --limit-burst is set by LOGBURST). If both parameters
          are set empty, no rate-limiting will occur.</para>

          <para>Example:</para>

          <programlisting>    LOGRATE=10/minute
    LOGBURST=5</programlisting>

          <para>For each logging rule, the first time the rule is reached, the
          packet will be logged; in fact, since the burst is 5, the first five
          packets will be logged. After this, it will be 6 seconds (1 minute
          divided by the rate of 10) before a message will be logged from the
          rule, regardless of how many packets reach it. Also, every 6 seconds
          which passes without matching a packet, one of the bursts will be
          regained; if no packets hit the rule for 30 seconds, the burst will
          be fully recharged; back where we started.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">LOGTAGONLY=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>Using the default LOGFORMAT, chain names may not exceed 11
          characters or truncation of the log prefix may occur. Longer chain
          names may be used with log tags if you set LOGTAGONLY=Yes. With
          LOGTAGONLY=Yes, if a log tag is specified then the tag is included
          in the log prefix in place of the chain name.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">MACLIST_DISPOSITION=</emphasis>[<emphasis
        role="bold">ACCEPT</emphasis>|<emphasis
        role="bold">DROP</emphasis>|<emphasis
        role="bold">REJECT</emphasis>]</term>

        <listitem>
          <para>Determines the disposition of connections requests that fail
          MAC Verification and must have the value ACCEPT (accept the
          connection request anyway), REJECT (reject the connection request)
          or DROP (ignore the connection request). If not set or if set to the
          empty value (e.g., MACLIST_DISPOSITION="") then
          MACLIST_DISPOSITION=REJECT is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">MACLIST_LOG_LEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>

        <listitem>
          <para>Determines the syslog level for logging connection requests
          that fail MAC Verification. The value must be a valid syslogd log
          level. If you don't want to log these connection requests, set to
          the empty value (e.g., MACLIST_LOG_LEVEL="").</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">MACLIST_TABLE=</emphasis>[<emphasis
        role="bold">filter</emphasis>|<emphasis
        role="bold">mangle</emphasis>]</term>

        <listitem>
          <para>Normally, MAC verification occurs in the filter table (INPUT
          and FORWARD) chains. When forwarding a packet from an interface with
          MAC verification to a bridge interface, that doesn't work.</para>

          <para>This problem can be worked around by setting
          MACLIST_TABLE=mangle which will cause Mac verification to occur out
          of the PREROUTING chain. Because REJECT isn't available in that
          environment, you may not specify MACLIST_DISPOSITION=REJECT with
          MACLIST_TABLE=mangle.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">MACLIST_TTL=[</emphasis><emphasis>number</emphasis>]</term>

        <listitem>
          <para>The performance of configurations with a large numbers of
          entries in <ulink
          url="shorewall-maclist.html">shorewall-maclist</ulink>(5) can be
          improved by setting the MACLIST_TTL variable in <ulink
          url="shorewall.conf.html">shorewall.conf</ulink>(5).</para>

          <para>If your iptables and kernel support the "Recent Match" (see
          the output of "shorewall check" near the top), you can cache the
          results of a 'maclist' file lookup and thus reduce the overhead
          associated with MAC Verification.</para>

          <para>When a new connection arrives from a 'maclist' interface, the
          packet passes through then list of entries for that interface in
          <ulink url="shorewall-maclist.html">shorewall-maclist</ulink>(5). If
          there is a match then the source IP address is added to the 'Recent'
          set for that interface. Subsequent connection attempts from that IP
          address occurring within $MACLIST_TTL seconds will be accepted
          without having to scan all of the entries. After $MACLIST_TTL from
          the first accepted connection request from an IP address, the next
          connection request from that IP address will be checked against the
          entire list.</para>

          <para>If MACLIST_TTL is not specified or is specified as empty (e.g,
          MACLIST_TTL="" or is specified as zero then 'maclist' lookups will
          not be cached).</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">MAPOLDACTIONS=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>Previously, Shorewall included a large number of standard
          actions (AllowPing, AllowFTP, ...). These have been replaced with
          parameterized macros. For compatibility, Shorewall can map the old
          names into invocations of the new macros if you set
          MAPOLDACTIONS=Yes. If this option is not set or is set to the empty
          value (MAPOLDACTIONS="") then MAPOLDACTIONS=Yes is assumed</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">MARK_IN_FORWARD_CHAIN=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>If your kernel has a FORWARD chain in the mangle table, you
          may set MARK_IN_FORWARD_CHAIN=Yes to cause the marking specified in
          the tcrules file to occur in that chain rather than in the
          PREROUTING chain. This permits you to mark inbound traffic based on
          its destination address when DNAT is in use. To determine if your
          kernel has a FORWARD chain in the mangle table, use the <emphasis
          role="bold">/sbin/shorewall show mangle</emphasis> command; if a
          FORWARD chain is displayed then your kernel will support this
          option. If this option is not specified or if it is given the empty
          value (e.g., MARK_IN_FORWARD_CHAIN="") then MARK_IN_FORWARD_CHAIN=No
          is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">MODULE_SUFFIX=</emphasis>[<emphasis
        role="bold">"</emphasis><emphasis>extension</emphasis> ...<emphasis
        role="bold">"</emphasis>]</term>

        <listitem>
          <para>The value of this option determines the possible file
          extensions of kernel modules. The default value is "o gz ko
          o.gz".</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">MODULESDIR=</emphasis>[<emphasis>pathname</emphasis>[<emphasis
        role="bold">:</emphasis><emphasis>pathname</emphasis>]...]</term>

        <listitem>
          <para>This parameter specifies the directory/directories where your
          kernel netfilter modules may be found. If you leave the variable
          empty, Shorewall will supply the value "/lib/modules/`uname
          -r`/kernel/net/ipv4/netfilter" in versions of Shorewall prior to
          3.2.4 and "/lib/modules/`uname
          -r`/kernel/net/ipv4/netfilter:/lib/modules/`uname
          -r`/kernel/net/ipv4/netfilter" in later versions.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">MUTEX_TIMEOUT=</emphasis>[<emphasis>seconds</emphasis>]</term>

        <listitem>
          <para>The value of this variable determines the number of seconds
          that programs will wait for exclusive access to the Shorewall lock
          file. After the number of seconds corresponding to the value of this
          variable, programs will assume that the last program to hold the
          lock died without releasing the lock.</para>

          <para>If not set or set to the empty value, a value of 60 (60
          seconds) is assumed.</para>

          <para>An appropriate value for this parameter would be twice the
          length of time that it takes your firewall system to process a
          <emphasis role="bold">shorewall restart</emphasis> command.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">OPTIMIZE=</emphasis>[<emphasis
        role="bold">0</emphasis>|<emphasis role="bold">1</emphasis>]</term>

        <listitem>
          <para>Traditionally, Shorewall has created rules for <ulink
          url="../ScalabilityAndPerformance.html">the complete matrix of host
          groups defined by the zones, interfaces and hosts files</ulink>. Any
          traffic that didn't correspond to an element of that matrix was
          rejected in one of the built-in chains. When the matrix is sparse,
          this results in lots of largely useless rules.</para>

          <para>These extra rules can be eliminated by setting
          OPTIMIZE=1.</para>

          <para>The OPTIMIZE setting also controls the suppression of
          redundant wildcard rules (those specifying "all" in the SOURCE or
          DEST column). A wildcard rule is considered to be redundant when it
          has the same ACTION and Log Level as the applicable policy.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">PATH=</emphasis><emphasis>pathname</emphasis>[<emphasis
        role="bold">:</emphasis><emphasis>pathname</emphasis>]...</term>

        <listitem>
          <para>Determines the order in which Shorewall searches directories
          for executable files.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">PKTTYPE=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>Normally Shorewall attempts to use the iptables packet type
          match extension to determine broadcast and multicast packets.</para>

          <orderedlist>
            <listitem>
              <para>This can cause a message to appear during shorewall start
              (modprobe: cant locate module ipt_pkttype).</para>
            </listitem>

            <listitem>
              <para>Some users have found problems with the packet match
              extension with the result that their firewall log is flooded
              with messages relating to broadcast packets.</para>
            </listitem>
          </orderedlist>

          <para>If you are experiencing either of these problems, setting
          PKTTYPE=No will prevent Shorewall from trying to use the packet type
          match extension and to use IP address matching to determine which
          packets are broadcasts or multicasts.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">RESTOREFILE=</emphasis><emphasis>filename</emphasis></term>

        <listitem>
          <para>Specifies the simple name of a file in /var/lib/shorewall to
          be used as the default restore script in the <emphasis
          role="bold">shorewall save</emphasis>, <emphasis
          role="bold">shorewall restore</emphasis>, <emphasis
          role="bold">shorewall forget </emphasis>and <emphasis
          role="bold">shorewall -f start</emphasis> commands.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">RETAIN_ALIASES=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>During <emphasis role="bold">shorewall star</emphasis>t, IP
          addresses to be added as a consequence of ADD_IP_ALIASES=Yes and
          ADD_SNAT_ALIASES=Yes are quietly deleted when <ulink
          url="shorewall-nat.html">shorewall-nat</ulink>(5) and <ulink
          url="shorewall-masq.html">shorewall-masq</ulink>(5) are processed
          then are re-added later. This is done to help ensure that the
          addresses can be added with the specified labels but can have the
          undesirable side effect of causing routes to be quietly deleted.
          When RETAIN_ALIASES is set to Yes, existing addresses will not be
          deleted. Regardless of the setting of RETAIN_ALIASES, addresses
          added during <emphasis role="bold">shorewall start</emphasis> are
          still deleted at a subsequent <emphasis role="bold">shorewall
          stop</emphasis> or <emphasis role="bold">shorewall
          restart</emphasis>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">RFC1918_LOG_LEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>

        <listitem>
          <para>This parameter determines the level at which packets logged
          under the <emphasis role="bold">norfc1918</emphasis> mechanism are
          logged. The value must be a valid syslog level and if no level is
          given, then info is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">RFC1918_STRICT=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>Traditionally, the RETURN target in the 'rfc1918' file has
          caused norfc1918 processing to cease for a packet if the packet's
          source IP address matches the rule. Thus, if you have this entry in
          <ulink
          url="shorewall-rfc1918.html">shorewall-rfc1918</ulink>(5):</para>

          <programlisting>    #SUBNETS                 TARGET
    192.168.1.0/24           RETURN</programlisting>

          <para>then traffic from 192.168.1.4 to 10.0.3.9 will be accepted
          even though you also have:</para>

          <programlisting>    #SUBNETS                 TARGET
    10.0.0.0/8               logdrop</programlisting>

          <para>Setting RFC1918_STRICT=Yes in shorewall.conf will cause such
          traffic to be logged and dropped since while the packet's source
          matches the RETURN rule, the packet's destination matches the
          'logdrop' rule.</para>

          <para>If not specified or specified as empty (e.g.,
          RFC1918_STRICT="") then RFC1918_STRICT=No is assumed.</para>

          <warning>
            <para>RFC1918_STRICT=Yes requires that your kernel and iptables
            support 'Connection Tracking' match.</para>
          </warning>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">ROUTE_FILTER=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>]</term>

        <listitem>
          <para>If this parameter is given the value <emphasis
          role="bold">Yes</emphasis> or <emphasis role="bold">yes</emphasis>
          then route filtering (anti-spoofing) is enabled on all network
          interfaces which are brought up while Shorewall is in the started
          state. The default value is <emphasis
          role="bold">no</emphasis>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">SAVE_IPSETS=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>If SAVE_IPSETS=Yes, then the current contents of your ipsets
          will be saved by the <emphasis role="bold">shorewall save</emphasis>
          command. Regardless of the setting of SAVE_IPSETS, if saved ipset
          contents are available then they will be restored by <emphasis
          role="bold">shorewall restore</emphasis>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">SHOREWALL_SHELL=</emphasis>[<emphasis>pathname</emphasis>]</term>

        <listitem>
          <para>This option is used to specify the shell program to be used to
          run the Shorewall compiler and to interpret the compiled script. If
          not specified or specified as a null value, /bin/sh is assumed.
          Using a light-weight shell such as ash or dash can significantly
          improve performance.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">SMURF_LOG_LEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>

        <listitem>
          <para>Specifies the logging level for smurf packets (see the
          nosmurfs option in <ulink
          url="shorewall-interfaces.html">shorewall-interfaces</ulink>(5)). If
          set to the empty value ( SMURF_LOG_LEVEL="" ) then smurfs are not
          logged.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">STARTUP_ENABLED=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>Determines if Shorewall is allowed to start. As released from
          shorewall.net, this option is set to <emphasis
          role="bold">No</emphasis>. When set to <emphasis
          role="bold">Yes</emphasis> or <emphasis role="bold">yes</emphasis>,
          Shorewall may be started. Used as a guard against Shorewall being
          accidentally started before it has been configured.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">SUBSYSLOCK=</emphasis>[<emphasis>pathname</emphasis>]</term>

        <listitem>
          <para>This parameter should be set to the name of a file that the
          firewall should create if it starts successfully and remove when it
          stops. Creating and removing this file allows Shorewall to work with
          your distribution's initscripts. For RedHat, this should be set to
          /var/lock/subsys/shorewall. For Debian, the value is
          /var/state/shorewall and in LEAF it is /var/run/shorwall.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">TC_ENABLED=</emphasis>[<emphasis
        role="bold">Yes</emphasis>|<emphasis
        role="bold">No</emphasis>|<emphasis
        role="bold">Internal</emphasis>]</term>

        <listitem>
          <para>If you say <emphasis role="bold">Yes</emphasis> or <emphasis
          role="bold">yes</emphasis> here, Shorewall will use a script that
          you supply to configure traffic shaping. The script must be named
          'tcstart' and must be placed in a directory on your
          CONFIG_PATH.</para>

          <para>If you say <emphasis role="bold">No</emphasis> or <emphasis
          role="bold">no</emphasis> then traffic shaping is not
          enabled.</para>

          <para>If you set TC_ENABLED=Internal or internal or leave the option
          empty then Shorewall will use its builtin traffic shaper
          (tc4shorewall written by Arne Bernin.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">TC_EXPERT=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>Normally, Shorewall tries to protect users from themselves by
          preventing PREROUTING and OUTPUT tcrules from being applied to
          packets that have been marked by the 'track' option in <ulink
          url="shorewall-providers.html">shorewall-providers</ulink>(5).</para>

          <para>If you know what you are doing, you can set TC_EXPERT=Yes and
          Shorewall will not include these cautionary checks.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">TCP_FLAGS_DISPOSITION=</emphasis>[<emphasis
        role="bold">ACCEPT</emphasis>|<emphasis
        role="bold">DROP</emphasis>|<emphasis
        role="bold">REJECT</emphasis>]</term>

        <listitem>
          <para>Determines the disposition of TCP packets that fail the checks
          enabled by the <emphasis role="bold">tcpflags</emphasis> interface
          option (see <ulink
          url="shorewall-interfaces.html">shorewall-interfaces</ulink>(5)) and
          must have a value of ACCEPT (accept the packet), REJECT (send an RST
          response) or DROP (ignore the packet). If not set or if set to the
          empty value (e.g., TCP_FLAGS_DISPOSITION="") then
          TCP_FLAGS_DISPOSITION=DROP is assumed.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">TCP_FLAGS_LOG_LEVEL=</emphasis>[<emphasis>log-level</emphasis>]</term>

        <listitem>
          <para>Determines the syslog level for logging packets that fail the
          checks enabled by the tcpflags interface option. The value must be a
          valid syslogd log level. If you don't want to log these packets, set
          to the empty value (e.g., TCP_FLAGS_LOG_LEVEL="").</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis role="bold">USE_ACTIONS=</emphasis>{<emphasis
        role="bold">Yes</emphasis>|<emphasis role="bold">No</emphasis>}</term>

        <listitem>
          <para>While Shorewall Actions can be very useful, they also require
          a sizable amount of code to implement. By setting USE_ACTIONS=No,
          embedded Shorewall installations can omit the large library
          /usr/share/shorewall/lib.actions.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><emphasis
        role="bold">VERBOSITY=</emphasis>[<emphasis>number</emphasis>]</term>

        <listitem>
          <para>Shorewall has traditionally been very noisy (produced lots of
          output). You may set the default level of verbosity using the
          VERBOSITY OPTION.</para>

          <para>Values are:</para>

          <simplelist>
            <member>0 — Silent. You may make it more verbose using the -v
            option</member>

            <member>1 — Major progress messages displayed</member>

            <member>2 — All progress messages displayed (pre Shorewall-3.2.0
            behavior)</member>
          </simplelist>

          <para>If not specified, then 2 is assumed.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>FILES</title>

    <para>/etc/shorewall/shorewall.conf</para>
  </refsect1>

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

    <para><ulink
    url="http://www.shorewall.net/Documentation.htm#Conf">http://www.shorewall.net/Documentation.htm#Conf</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_rules(5), shorewall-routestopped(5), shorewall-rules(5),
    shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5),
    shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)</para>
  </refsect1>
</refentry>