shorewall_code/docs/Anatomy.xml

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<article>
  <!--$Id$-->

  <articleinfo>
    <title>Anatomy of Shorewall 4.0</title>

    <authorgroup>
      <author>
        <firstname>Tom</firstname>

        <surname>Eastep</surname>
      </author>
    </authorgroup>

    <pubdate><?dbtimestamp format="Y/m/d"?></pubdate>

    <copyright>
      <year>2007</year>

      <holder>Thomas M. Eastep</holder>
    </copyright>

    <legalnotice>
      <para>Permission is granted to copy, distribute and/or modify this
      document under the terms of the GNU Free Documentation License, Version
      1.2 or any later version published by the Free Software Foundation; with
      no Invariant Sections, with no Front-Cover, and with no Back-Cover
      Texts. A copy of the license is included in the section entitled
      <quote><ulink url="GnuCopyright.htm">GNU Free Documentation
      License</ulink></quote>.</para>
    </legalnotice>
  </articleinfo>

  <section id="Products">
    <title>Products</title>

    <para>Shorewall 4.0 consists of four packages.</para>

    <orderedlist>
      <listitem>
        <para><emphasis role="bold">Shorewall-common</emphasis>. This package
        must be installed on at least one system in your network. That system
        must also have Shorewall-shell and/or Shorewall-perl installed.</para>
      </listitem>

      <listitem>
        <para><emphasis role="bold">Shorewall-shell</emphasis>. This package
        includes the legacy Shorewall configuration compiler written in Bourne
        Shell. This compiler is very portable but suffers from performance
        problems and has become hard to maintain.</para>
      </listitem>

      <listitem>
        <para><emphasis role="bold">Shorewall-perl</emphasis>. An alternative
        to Shorewall-shell written in the Perl language. This compiler is
        highly portable to those Unix-like platforms that support Perl
        (including Cygwin) and is the compiler of choice for new Shorewall
        installations.</para>
      </listitem>

      <listitem>
        <para><emphasis role="bold">Shorewall-lite</emphasis>. Shorewall
        allows for central administration of multiple firewalls through use of
        Shorewall lite. The full Shorewall product (along with Shorewall-shell
        and/or Shorewall-perl) are installed on a central administrative
        system where compiled Shorewall scripts are generated. These scripts
        are copied to the firewall systems where they run under the control of
        Shorewall-lite.</para>
      </listitem>
    </orderedlist>
  </section>

  <section id="Shorewall">
    <title>Shorewall-common</title>

    <para>The Shorewall-common package includes a large number of files which
    are installed in /<filename class="directory">sbin</filename>, <filename
    class="directory">/usr/share/shorewall</filename>, <filename
    class="directory">/etc/shorewall</filename>,
    <filename>/etc/init.d</filename> and <filename
    class="directory">/var/lilb/shorewall/</filename>. These are described in
    the sub-sections that follow.</para>

    <section id="sbin">
      <title>/sbin</title>

      <para>The <filename>/sbin/shorewall</filename> shell program is use to
      interact with Shorewall. See <ulink
      url="manpages/shorewall.html">shorewall</ulink>(8).</para>
    </section>

    <section id="share-shorewall">
      <title>/usr/share/shorewall</title>

      <para>The bulk of Shorewall is installed here.</para>

      <itemizedlist>
        <listitem>
          <para><filename>action.template</filename> - template file for
          creating <ulink url="Actions.html">actions</ulink>.</para>
        </listitem>

        <listitem>
          <para><filename>action.*</filename> - standard Shorewall
          actions.</para>
        </listitem>

        <listitem>
          <para><filename>actions.std</filename> - file listing the standard
          actions.</para>
        </listitem>

        <listitem>
          <para><filename class="directory">configfiles</filename> - A
          directory containing configuration files to copy to create a <ulink
          url="CompiledPrograms.html#Lite">Shorewall-lite export
          directory.</ulink></para>
        </listitem>

        <listitem>
          <para><filename><filename>configpath</filename></filename> - A file
          containing distribution-specific path assignments.</para>
        </listitem>

        <listitem>
          <para><filename>firewall</filename> - A shell program that handles
          the <command>add</command> and <command>delete</command> commands
          (see <ulink url="manpages/shorewall.html">shorewall</ulink>(8)). It
          also handles the <command>stop</command> and
          <command>clear</command> commands when there is no current compiled
          firewall script on the system.</para>
        </listitem>

        <listitem>
          <para><filename class="symlink">functions</filename> - A symbolic
          link to <filename>lib.base</filename> that provides for
          compatibility with older versions of Shorewall.</para>
        </listitem>

        <listitem>
          <para><filename class="symlink">init</filename> - A symbolic link to
          the init script (usually
          <filename>/etc/init.d/shorewall</filename>).</para>
        </listitem>

        <listitem>
          <para><filename>lib.*</filename> - Shell function libraries used by
          the other shell programs.</para>
        </listitem>

        <listitem>
          <para><filename>macro.*</filename> - The standard Shorewall <ulink
          url="Macros.html">macros</ulink>.</para>
        </listitem>

        <listitem>
          <para><filename>modules</filename> - File that drives the loading of
          Netfilter kernel modules. May be overridden by
          <filename>/etc/shorewall/modules</filename>.</para>
        </listitem>

        <listitem>
          <para><filename>version</filename> - A file containing the currently
          install version of Shorewall.</para>
        </listitem>

        <listitem>
          <para><filename>wait4ifup</filename> - A shell program that <ulink
          url="shorewall_extension_scripts.htm">extension scripts</ulink> can
          use to delay until a network interface is available.</para>
        </listitem>
      </itemizedlist>
    </section>

    <section id="shorewall">
      <title>/etc/shorewall</title>

      <para>This is where the modifiable configuration files are
      installed.</para>
    </section>

    <section id="init">
      <title>/etc/init.d or /etc/rc.d (depends on distribution)</title>

      <para>An init script is installed here. Depending on the distribution,
      it is named <filename>shorewall</filename> or
      <filename>rc.firewall</filename>.</para>
    </section>

    <section id="var">
      <title>/var/lib/shorewall</title>

      <para>Shorewall doesn't install any files in this directory but rather
      uses the directory for storing state information. This directory may be
      relocated using <ulink
      url="manpages/shorewall-vardir.html">shorewall-vardir</ulink>(5).</para>

      <itemizedlist>
        <listitem>
          <para><filename>chains</filename> - If DYNAMIC_ZONES=Yes in <ulink
          url="manpages/shorewall.conf.html">shorewall.conf</ulink>(5), this
          file contains information used by the <command>add</command> and
          <command>delete</command> commands (see <ulink
          url="manpages/shorewall.html">shorewall</ulink>(8)).</para>
        </listitem>

        <listitem>
          <para><filename>.iptables-restore-input </filename>- The file passed
          as input to the iptables-restore program to initialize the firewall
          during the last <command>start</command> or
          <command>restart</command> command (see <ulink
          url="manpages/shorewall.html">shorewall</ulink>(8)).</para>
        </listitem>

        <listitem>
          <para><filename>.modules</filename> - The contents of the modules
          file used during the last <command>start</command> or
          <command>restart</command> command (see <ulink
          url="manpages/shorewall.html">shorewall</ulink>(8) for command
          information).</para>
        </listitem>

        <listitem>
          <para><filename>.modulesdir</filename> - The MODULESDIR setting
          (<ulink
          url="manpages/shorewall.conf.html">shorewall.conf</ulink>(5)) at the
          last <command>start</command> or <command>restart.</command></para>
        </listitem>

        <listitem>
          <para><filename>nat</filename> - This unfortunately-named file
          records the IP addresses added by ADD_SNAT_ALIASES=Yes and
          ADD_IP_ALIASES=Yes in <ulink
          url="manpages/shorewall.conf.html">shorewall.conf</ulink>(5).</para>
        </listitem>

        <listitem>
          <para><filename>proxyarp</filename> - Records the arp entries added
          by entries in <ulink
          url="manpages/shorewall-proxyarp.html">shorewall-proxyarp</ulink>(5).</para>
        </listitem>

        <listitem>
          <para><filename>.refresh</filename> - The shell program that
          performed the last successful <command>refresh</command>
          command.</para>
        </listitem>

        <listitem>
          <para><filename>.restart</filename> - The shell program that
          performed the last successful <command>restart</command>
          command.</para>
        </listitem>

        <listitem>
          <para><filename>restore</filename> - The default shell program used
          to execute <command>restore</command> commands.</para>
        </listitem>

        <listitem>
          <para><filename>.restore</filename> - The shell program that
          performed the last successful <command>refresh, restart</command> or
          <command>start</command> command.</para>
        </listitem>

        <listitem>
          <para><filename>save</filename> - File created by the
          <command>save</command> command and used to restore the dynamic
          blacklist during <command>start/restart</command>.</para>
        </listitem>

        <listitem>
          <para><filename>.start</filename> - The shell program that performed
          the last successful <command>start</command> command.</para>
        </listitem>

        <listitem>
          <para><filename>state</filename> - Records the current firewall
          state.</para>
        </listitem>

        <listitem>
          <para><filename>zones</filename> - Records the current zone
          contents.</para>
        </listitem>
      </itemizedlist>
    </section>
  </section>

  <section id="Shorewall-shell">
    <title>Shorewall-shell</title>

    <para>The Shorewall-shell product installs all of its files in
    /usr/share/<filename class="directory">shorewall-shell</filename>.</para>

    <itemizedlist>
      <listitem>
        <para><filename>compiler</filename> - The configuration compiler shell
        program.</para>
      </listitem>

      <listitem>
        <para><filename>lib.*</filename> - Shell function libraries used by
        the compiler. On embedded systems, only a sub-set of the available
        libraries may be installed as a space-saving measure.</para>
      </listitem>

      <listitem>
        <para><filename>prog.*</filename> - Shell program fragments used as
        input to the compiler.</para>
      </listitem>

      <listitem>
        <para><filename>version</filename> - A file containing the currently
        install version of Shorewall-shell.</para>
      </listitem>
    </itemizedlist>
  </section>

  <section id="Shorewall-perl">
    <title>Shorewall-perl</title>

    <para>The Shorewall-perl product installs all of its files in
    /usr/share/<filename class="directory">shorewall-perl</filename>.</para>

    <itemizedlist>
      <listitem>
        <para><filename>buildports.pl</filename> - A Perl program that builds
        the Shorewall/Ports.pm module during installation (This program is
        removed in Shorewall 4.0.5 and later releases)</para>
      </listitem>

      <listitem>
        <para><filename>compiler.pl</filename> - The configuration compiler
        perl program.</para>
      </listitem>

      <listitem>
        <para><filename>prog.*</filename> - Shell program fragments used as
        input to the compiler.</para>
      </listitem>

      <listitem>
        <para><filename class="directory">Shorewall</filename> - Directory
        containing the Shorewall Perl modules used by the compiler.</para>
      </listitem>

      <listitem>
        <para><filename>version</filename> - A file containing the currently
        install version of Shorewall-shell.</para>
      </listitem>
    </itemizedlist>
  </section>

  <section id="Shorewall-lite">
    <title>Shorewall-lite</title>

    <para>The Shorewall-lite product includes files installed in /<filename
    class="directory">sbin</filename>, <filename
    class="directory">/usr/share/shorewall-lite</filename>, /etc/<filename
    class="directory">shorewall-lite</filename>,
    <filename>/etc/init.d</filename> and <filename
    class="directory">/var/lilb/shorewall/</filename>. These are described in
    the sub-sections that follow.</para>

    <section id="sbin-lite">
      <title>/sbin</title>

      <para>The <filename>/sbin/shorewall-lite</filename> shell program is use
      to interact with Shorewall lite. See <ulink
      url="manpages/shorewall-lite.html">shorewall-lite</ulink>(8).</para>
    </section>

    <section id="init-lite">
      <title>/etc/init.d or /etc/rc.d (depends on distribution)</title>

      <para>An init script is installed here. Depending on the distribution,
      it is named <filename>shorewall-lite</filename> or
      <filename>rc.firewall</filename>.</para>
    </section>

    <section id="shorewall-lite">
      <title>/etc/shorewall-lite</title>

      <para>This is where the modifiable configuration files are
      installed.</para>
    </section>

    <section id="share-lite">
      <title>/usr/share/shorewall-lite</title>

      <para>The bulk of Shorewall-lite is installed here.</para>

      <itemizedlist>
        <listitem>
          <para><filename><filename>configpath</filename></filename> - A file
          containing distribution-specific path assignments.</para>
        </listitem>

        <listitem>
          <para><filename class="symlink">functions</filename> - A symbolic
          link to <filename>lib.base</filename> that provides for
          compatibility with older versions of Shorewall.</para>
        </listitem>

        <listitem>
          <para><filename>lib.*</filename> - Shell function libraries used by
          the other shell programs. These are copies of the corresponding
          libraries in the Shorewall product.</para>
        </listitem>

        <listitem>
          <para><filename>modules</filename> - File that drives the loading of
          Netfilter kernel modules. May be overridden by
          <filename>/etc/shorewall-lite/modules</filename>.</para>
        </listitem>

        <listitem>
          <para><filename>shorecap</filename> - A shell program used for
          generating capabilities files. See the <ulink
          url="CompiledPrograms.html#Lite">Shorewall-lite
          documentation</ulink>.</para>
        </listitem>

        <listitem>
          <para><filename>version</filename> - A file containing the currently
          install version of Shorewall.</para>
        </listitem>

        <listitem>
          <para><filename>wait4ifup</filename> - A shell program that <ulink
          url="shorewall_extension_scripts.htm">extension scripts</ulink> can
          use to delay until a network interface is available.</para>
        </listitem>
      </itemizedlist>
    </section>

    <section id="var-lite">
      <title>/var/lib/shorewall-lite</title>

      <para>Shorewall-lite doesn't install any files in this directory but
      rather uses the directory for storing state information. This directory
      may be relocated using <ulink
      url="manpages/shorewall-lite-vardir.html">shorewall-lite-vardir</ulink>(5).</para>

      <itemizedlist>
        <listitem>
          <para><filename>firewall</filename> - Compiled shell script
          installed by running the load or reload command on the
          administrative system (see <ulink
          url="manpages/shorewall.html">shorewall</ulink>(8)).</para>
        </listitem>

        <listitem>
          <para><filename>firewall.conf</filename> - Digest of the
          shorewall.conf file used to compile the firewall script on the
          administrative system.</para>
        </listitem>
      </itemizedlist>

      <itemizedlist>
        <listitem>
          <para><filename>.iptables-restore-input </filename>- The file passed
          as input to the iptables-restore program to initialize the firewall
          during the last <command>start</command> or
          <command>restart</command> command (see <ulink
          url="manpages/shorewall-lite.html">shorewall-lite</ulink>(8)).</para>
        </listitem>

        <listitem>
          <para><filename>.modules</filename> - The contents of the modules
          file used during the last <command>start</command> or
          <command>restart</command> command (see <ulink
          url="manpages/shorewall-lite.html">shorewall-lite</ulink>(8) for
          command information).</para>
        </listitem>

        <listitem>
          <para><filename>.modulesdir</filename> - The MODULESDIR setting
          (<ulink
          url="manpages/shorewall.conf.html">shorewall.conf</ulink>(5)) at the
          last <command>start</command> or <command>restart.</command></para>
        </listitem>

        <listitem>
          <para><filename>nat</filename> - This unfortunately-named file
          records the IP addresses added by ADD_SNAT_ALIASES=Yes and
          ADD_IP_ALIASES=Yes in <ulink
          url="manpages/shorewall.conf.html">shorewall.conf</ulink>(5).</para>
        </listitem>

        <listitem>
          <para><filename>proxyarp</filename> - Records the arp entries added
          by entries in <ulink
          url="manpages/shorewall-proxyarp.html">shorewall-proxyarp</ulink>(5).</para>
        </listitem>

        <listitem>
          <para><filename>.refresh</filename> - The shell program that
          performed the last successful <command>refresh</command>
          command.</para>
        </listitem>

        <listitem>
          <para><filename>.restart</filename> - The shell program that
          performed the last successful <command>restart</command>
          command.</para>
        </listitem>

        <listitem>
          <para><filename>restore</filename> - The default shell program used
          to execute <command>restore</command> commands.</para>
        </listitem>

        <listitem>
          <para><filename>.restore</filename> - The shell program that
          performed the last successful <command>refresh, restart</command> or
          <command>start</command> command.</para>
        </listitem>

        <listitem>
          <para><filename>save</filename> - File created by the
          <command>save</command> command and used to restore the dynamic
          blacklist during <command>start/restart</command>.</para>
        </listitem>

        <listitem>
          <para><filename>.start</filename> - The shell program that performed
          the last successful <command>start</command> command.</para>
        </listitem>

        <listitem>
          <para><filename>state</filename> - Records the current firewall
          state.</para>
        </listitem>

        <listitem>
          <para><filename>zones</filename> - Records the current zone
          contents.</para>
        </listitem>
      </itemizedlist>
    </section>
  </section>
</article>