shorewall_code/docs/Dynamic.xml

159 lines
5.3 KiB
XML
Raw Normal View History

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
<article>
<!--$Id$-->
<articleinfo>
<title>Dynamic Zones</title>
<authorgroup>
<author>
<firstname>Tom</firstname>
<surname>Eastep</surname>
</author>
</authorgroup>
<pubdate><?dbtimestamp format="Y/m/d"?></pubdate>
<copyright>
<year>2009</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>
<title>Overview</title>
<para>There is sometimes a need to be able to define a zone whose members
are unknown at compile-time. For example, you may wish to require
authentication of internal users before allowing them access to the
internet. When a user is authenticated, the user's IP address is added to
the zone of users permitted web access.</para>
<para>Shorewall provides basic support for defining such zones. This
support is based on <ulink
url="http://ipset.netfilter.org/">ipset</ulink>, so to use dynamic zones,
you must have installed the <ulink
url="http://xtables-addons.sourceforge.net/">xtables-addons</ulink>.</para>
</section>
<section>
<title>Defining a Dynamic Zone</title>
<para>A dynamic zone is defined by using the keyword dynamic in the zones
host list.</para>
<para>Example:</para>
<blockquote>
<para><filename>/etc/shorewall/zones</filename>:<programlisting>#NAME TYPE OPTIONS
loc ipv4
webok:loc ipv4</programlisting><filename>/etc/shorewall/interfaces</filename>:</para>
<programlisting>#ZONE INTERFACE BROADCAST OPTIONS
webok eth0 - hosts=dynamic</programlisting>
</blockquote>
<para>Once the above definition is added, Shorewall will automatically
create an ipset named <emphasis>webok_eth0</emphasis> the next time that
Shorewall is started or restarted. Shorewall will create an ipset of type
<firstterm>iphash</firstterm>. If you want to use a different type of
ipset, such as <firstterm>macipmap</firstterm>, then you will want to
manually create that ipset yourself before the next Shorewall
start/restart.</para>
</section>
<section>
<title>Adding a Host to a Dynamic Zone</title>
<para>Adding a host to a dynamic zone is accomplished by adding the host's
IP address to the appropriate ipset. Shorewall provldes a command for
doing that:</para>
<blockquote>
<para><command>shorewall add</command> <replaceable>interface:address
...</replaceable> <replaceable>zone</replaceable></para>
</blockquote>
<para>Example:</para>
<blockquote>
<para><command>shorewall add eth0:192.168.3.4 webok</command></para>
</blockquote>
</section>
<section>
<title>Deleting a Host from a Dynamic Zone</title>
<para>Deleting a host from a dynamic zone is accomplished by removing the
host's IP address from the appropriate ipset. Shorewall provldes a command
for doing that:</para>
<blockquote>
<para><command>shorewall delete</command> <replaceable>interface:address
...</replaceable> <replaceable>zone</replaceable></para>
</blockquote>
<para>Example:</para>
<blockquote>
<para><command>shorewall delete eth0:192.168.3.4 webok</command></para>
</blockquote>
</section>
<section>
<title>Listing the Contents of a Dynamic Zone</title>
<para>The shorewall show command may be used to list the current contents
of a dynamic zone.</para>
<blockquote>
<para><command>shorewall show dynamic</command>
<replaceable>zone</replaceable></para>
</blockquote>
<para>Example:</para>
<blockquote>
<programlisting><command>shorewall show dynamic webok</command>
eth0:
192.168.3.4
192.168.3.9</programlisting>
</blockquote>
</section>
<section>
<title>Dynamic Zone Contents and Shorewall stop/start/restart</title>
<para>The contents of a dynamic zone survive <command>shorewall
2009-05-06 16:14:31 +02:00
stop/shorewall start</command> and <command>shorewall restart</command>.
During <command>shorewall stop</command>, the contents of the ipsets are
saved in the file <filename>${VARDIR}/ipsets.save</filename> (usually
<filename>/var/lib/shorewall/ipsets.save</filename>). During
<command>shorewall start</command>, the contents of that file are restored
to the sets. During both <command>shorewall start</command> and
<command>shorewall restart</command>, any new ipsets required as a result
of a configuration change are added.</para>
</section>
<section>
<title>Restrictions</title>
<para>When using dynamic zones, you may not use ipsets in your
<filename>/etc/shorewall/routestopped</filename> file.</para>
</section>
</article>