forked from extern/shorewall_code
416 lines
14 KiB
XML
416 lines
14 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
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"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
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<article>
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<!--$Id$-->
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<articleinfo>
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<title>Dynamic Zones</title>
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<authorgroup>
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<author>
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<firstname>Tom</firstname>
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<surname>Eastep</surname>
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</author>
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</authorgroup>
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<pubdate><?dbtimestamp format="Y/m/d"?></pubdate>
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<copyright>
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<year>2009</year>
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<holder>Thomas M. Eastep</holder>
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</copyright>
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<legalnotice>
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<para>Permission is granted to copy, distribute and/or modify this
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document under the terms of the GNU Free Documentation License, Version
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1.2 or any later version published by the Free Software Foundation; with
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no Invariant Sections, with no Front-Cover, and with no Back-Cover
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Texts. A copy of the license is included in the section entitled
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<quote><ulink url="GnuCopyright.htm">GNU Free Documentation
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License</ulink></quote>.</para>
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</legalnotice>
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</articleinfo>
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<section>
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<title>Overview</title>
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<para>There is sometimes a need to be able to define a zone whose members
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are unknown at compile-time. For example, you may wish to require
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authentication of internal users before allowing them access to the
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internet. When a user is authenticated, the user's IP address is added to
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the zone of users permitted web access.</para>
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<para>Shorewall provides basic support for defining such zones. This
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support is based on <ulink
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url="http://ipset.netfilter.org/">ipset</ulink>. As of this writing, ipset
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is not included in the standard kernel distribution; so to use dynamic
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zones, you must be running kernel 2.6.20 or later and have installed the
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<ulink
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url="http://xtables-addons.sourceforge.net/">xtables-addons</ulink>.</para>
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</section>
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<section id="xtables-addons">
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<title>Installing xtables-addons</title>
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<para>The xtables-addons are fairly easy to install. You do not need to
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recompile your kernel.</para>
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<para><trademark>Debian</trademark> users can find xtables-addons-common
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and xtables-addons-source packages in <firstterm>testing</firstterm>. The
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kernel modules can be built and installed with the help of
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module-assistant. As of this writing, these packages are in the
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<firstterm>admin</firstterm> group rather than in the
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<firstterm>network</firstterm> group!!??</para>
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<para>For other users, the basic steps are as follows:</para>
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<orderedlist>
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<listitem>
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<para>Install gcc and make</para>
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</listitem>
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<listitem>
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<para>Install the headers for the kernel you are running. In some
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distributions, such as <trademark>Debian</trademark> and
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<trademark>Ubuntu</trademark>, the packet is called kernel-headers.
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For other distrubutions, such as OpenSuSE, you must install the
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kernel-source package.</para>
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</listitem>
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<listitem>
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<para>download the iptables source tarball</para>
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</listitem>
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<listitem>
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<para>untar the source</para>
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</listitem>
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<listitem>
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<para>cd to the iptables source directory</para>
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</listitem>
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<listitem>
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<para>run 'make'</para>
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</listitem>
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<listitem>
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<para>as root, run 'make install'</para>
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</listitem>
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<listitem>
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<para>Your new iptables binary will now be installed in
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/usr/local/sbin. Modify shorewall.conf to specify
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IPTABLES=/usr/local/sbin/iptables</para>
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</listitem>
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<listitem>
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<para>Download the latest xtables-addons source tarball</para>
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</listitem>
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<listitem>
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<para>Untar the xtables-addons source</para>
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</listitem>
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<listitem>
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<para>cd to the xtables-addons source directory</para>
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</listitem>
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<listitem>
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<para>run './configure'</para>
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</listitem>
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<listitem>
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<para>run 'make'</para>
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</listitem>
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<listitem>
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<para>As root, cd to the xtables-addons directory and run 'make
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install'.</para>
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</listitem>
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<listitem>
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<para>Restart shorewall</para>
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</listitem>
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<listitem>
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<para>'shorewall show capabilities' should now indicate<emphasis
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role="bold"> Ipset Match: Available</emphasis></para>
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</listitem>
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</orderedlist>
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<para>You will have to repeat steps 10-13 each time that you receive a
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kernel upgrade from your distribution vendor. You can install
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xtables-addons before booting to the new kernel as follows
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(<emphasis>new-kernel-version</emphasis> is the version of the
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newly-installed kernel - example <emphasis
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role="bold">2.6.28.11-generic</emphasis>. Look in the /lib/modules
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directory to get the full version name)</para>
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<orderedlist>
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<listitem>
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<para>cd to the xtables-addons source directory</para>
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</listitem>
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<listitem>
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<para>run 'make clean'</para>
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</listitem>
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<listitem>
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<para>run './configure
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--with-kbuild=/lib/modules/<emphasis>new-kernel-version</emphasis>/build
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--with-ksource=/lib/modules/<emphasis>new-kernel-version</emphasis>/source'</para>
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</listitem>
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<listitem>
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<para>run 'make'</para>
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</listitem>
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<listitem>
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<para>As root, cd to the xtables-addons source directory and run 'make
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install'.</para>
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</listitem>
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<listitem>
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<para>As root, run 'depmod -a
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<emphasis>new-kernel-version'</emphasis></para>
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</listitem>
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</orderedlist>
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</section>
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<section>
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<title>Dynamic Zones -- Shorewall 4.5.9 and Later</title>
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<para>Prior to Shorewall 4.5.9, when multiple records for a zone appear in
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<filename>/etc/shorewall/hosts</filename>, Shorewall would create a
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separate ipset for each interface. This meant that an add or delete
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command was required for each of the interface, when the address involved
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was reachable via multiple interfaces.</para>
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<para>Beginning with Shoreawll 4.5.9, it is possible to have a single
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ipset shared among all interfaces. This also simplifies management of
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dynamic zone contents for dynamic zones associated with only a single
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interface.</para>
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<para>The earlier implementation described below is still available in
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these later releases.</para>
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<section id="defining">
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<title>Defining a Dynamic Zone</title>
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<para>A dynamic zone is defined by specifying the <emphasis
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role="bold">dynamic_shared</emphasis> option in the zones file and using
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the <emphasis role="bold">dynamic</emphasis> keyword in the hosts
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list.</para>
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<para><filename>/etc/shorewall/zones</filename>:<programlisting>#NAME TYPE OPTIONS
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net ipv4
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rsyncok:loc ipv4 <emphasis role="bold">dynamic_shared</emphasis></programlisting><filename>/etc/shorewall/interfaces</filename>:</para>
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<programlisting>#ZONE INTERFACE BROADCAST OPTIONS
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loc eth0 - …
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loc eth1 - …</programlisting>
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<para><filename>/etc/shorewall/hosts</filename>:</para>
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<programlisting>#ZONE HOSTS OPTIONS
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rsyncok eth0:<emphasis role="bold">dynamic</emphasis>
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rsyncok eth1:<emphasis role="bold">dynamic</emphasis></programlisting>
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<para>When the <emphasis role="bold">dynamic_shared</emphasis> option is
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specified, a single ipset is created; the ipset has the same name as the
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zone.</para>
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</section>
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<section id="Adding">
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<title>Adding a Host to a Dynamic Zone.</title>
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<para>Adding a host to a dynamic zone is accomplished by adding the
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host's IP address to the appropriate ipset. Shorewall provldes a command
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for doing that:<blockquote>
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<para><command>shorewall add</command> <replaceable>zone
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address</replaceable> ...</para>
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</blockquote></para>
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<para>Example:</para>
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<blockquote>
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<para><command>shorewall add rsyncok 70.90.191.124</command></para>
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</blockquote>
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</section>
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<section id="delete">
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<title>Deleting a Host from a Dynamic Zone</title>
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<para>Deleting a host from a dynamic zone is accomplished by removing
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the host's IP address from the appropriate ipset. Shorewall provldes a
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command for doing that:</para>
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<blockquote>
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<para><command>shorewall delete</command>
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<replaceable>zone</replaceable> <replaceable>address</replaceable>
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...</para>
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</blockquote>
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<para>Example:</para>
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<blockquote>
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<para><command>shorewall delete rsyncok 70.19.191.124</command></para>
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</blockquote>
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<para>The command can only be used when the ipset involved is of type
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iphash. For other ipset types, the <command>ipset</command> command must
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be used directly.</para>
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</section>
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<section id="listing">
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<title>Listing the Contents of a Dynamic Zone</title>
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<para>The shorewall show command may be used to list the current
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contents of a dynamic zone.</para>
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<blockquote>
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<para><command>shorewall show dynamic</command>
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<replaceable>zone</replaceable></para>
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</blockquote>
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<para>Example:</para>
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<blockquote>
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<programlisting><command>shorewall show dynamic rsyncok</command>
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rsyncok:
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70.90.191.122
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70.90.191.124</programlisting>
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</blockquote>
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</section>
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</section>
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<section id="Version-4.5.9">
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<title>Dynamic Zones -- Shorewall 5.4.8 and Earlier.</title>
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<para>The method described in this section is still supported in the later
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releases.</para>
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<section id="defining1">
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<title>Defining a Dynamic Zone</title>
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<para>A dynamic zone is defined by using the keyword <emphasis
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role="bold">dynamic</emphasis> in the zones host list.</para>
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<para>Example:</para>
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<blockquote>
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<para><filename>/etc/shorewall/zones</filename>:<programlisting>#NAME TYPE OPTIONS
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loc ipv4
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webok:loc ipv4</programlisting><filename>/etc/shorewall/interfaces</filename>:</para>
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<programlisting>#ZONE INTERFACE BROADCAST OPTIONS
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loc eth0 - …
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</programlisting>
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<para><filename>/etc/shorewall/hosts</filename>:</para>
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<programlisting>#ZONE HOSTS OPTIONS
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webok eth0:<emphasis role="bold">dynamic</emphasis></programlisting>
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</blockquote>
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<para>Once the above definition is added, Shorewall will automatically
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create an ipset named <emphasis>webok_eth0</emphasis> the next time that
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Shorewall is started or restarted. Shorewall will create an ipset of
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type <firstterm>iphash</firstterm>. If you want to use a different type
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of ipset, such as <firstterm>macipmap</firstterm>, then you will want to
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manually create that ipset yourself before the next Shorewall
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start/restart.</para>
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<para>The dynamic zone capability was added to Shorewall6 in Shorewall
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4.4.21.</para>
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</section>
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<section id="adding1">
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<title>Adding a Host to a Dynamic Zone</title>
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<para>Adding a host to a dynamic zone is accomplished by adding the
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host's IP address to the appropriate ipset. Shorewall provldes a command
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for doing that:</para>
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<blockquote>
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<para><command>shorewall add</command> <replaceable>interface:address
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...</replaceable> <replaceable>zone</replaceable></para>
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</blockquote>
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<para>Example:</para>
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<blockquote>
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<para><command>shorewall add eth0:192.168.3.4 webok</command></para>
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</blockquote>
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<para>The command can only be used when the ipset involved is of type
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iphash. For other ipset types, the <command>ipset</command> command must
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be used directly.</para>
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</section>
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<section id="deleting">
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<title>Deleting a Host from a Dynamic Zone</title>
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<para>Deleting a host from a dynamic zone is accomplished by removing
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the host's IP address from the appropriate ipset. Shorewall provldes a
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command for doing that:</para>
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<blockquote>
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<para><command>shorewall delete</command>
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<replaceable>interface:address ...</replaceable>
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<replaceable>zone</replaceable></para>
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</blockquote>
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<para>Example:</para>
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<blockquote>
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<para><command>shorewall delete eth0:192.168.3.4
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webok</command></para>
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</blockquote>
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<para>The command can only be used when the ipset involved is of type
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iphash. For other ipset types, the <command>ipse t</command> command
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must be used directly.</para>
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</section>
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<section id="listing1">
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<title>Listing the Contents of a Dynamic Zone</title>
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<para>The shorewall show command may be used to list the current
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contents of a dynamic zone.</para>
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<blockquote>
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<para><command>shorewall show dynamic</command>
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<replaceable>zone</replaceable></para>
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</blockquote>
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<para>Example:</para>
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<blockquote>
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<programlisting><command>shorewall show dynamic webok</command>
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eth0:
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192.168.3.4
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192.168.3.9</programlisting>
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</blockquote>
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</section>
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</section>
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<section id="start-stop">
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<title>Dynamic Zone Contents and Shorewall stop/start/restart</title>
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<para>When SAVE_IPSETS=Yes in shorewall.conf, the contents of a dynamic
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zone survive <command>shorewall stop/shorewall start</command> and
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<command>shorewall restart</command>. During <command>shorewall
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stop</command>, the contents of the ipsets are saved in the file
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<filename>${VARDIR}/ipsets.save</filename> (usually
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<filename>/var/lib/shorewall/ipsets.save</filename>). During
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<command>shorewall start</command>, the contents of that file are restored
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to the sets. During both <command>shorewall start</command> and
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<command>shorewall restart</command>, any new ipsets required as a result
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of a configuration change are added.</para>
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</section>
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</article>
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