shorewall_code/manpages/shorewall-zones.xml
teastep 6892bfbf5d Correct calculation
Signed-off-by: Tom Eastep <teastep@shorewall.net>

git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@9691 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
2009-03-15 19:49:18 +00:00

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
<refentry>
<refmeta>
<refentrytitle>shorewall-zones</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>zones</refname>
<refpurpose>Shorewall zone declaration file</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>/etc/shorewall/zones</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>The /etc/shorewall/zones file declares your network zones. You
specify the hosts in each zone through entries in
<filename>/etc/shorewall/interfaces</filename> or
<filename>/etc/shorewall/hosts</filename>.</para>
<para>The columns in the file are as follows.</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">ZONE</emphasis> -
<emphasis>zone</emphasis>[<emphasis
role="bold">:</emphasis><emphasis>parent-zone</emphasis>[<emphasis
role="bold">,</emphasis><emphasis>parent-zone</emphasis>]...]</term>
<listitem>
<para>Name of the <emphasis>zone</emphasis>. The names "all",
"none", "SOURCE" and "DEST" are reserved and may not be used as zone
names. The maximum length of a zone name is determined by the
setting of the LOGFORMAT option in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5). With the
default LOGFORMAT, zone names can be at most 5 characters
long.</para>
<blockquote>
<para>The maximum length of an iptables log prefix is 29 bytes. As
explained in <ulink
url="shorewall.conf.html">shorewall.conf</ulink> (5), the default
LOGPREFIX formatting string is “Shorewall:%s:%s:” where the first
%s is replaced by the chain name and the second is replaced by the
disposition.</para>
<itemizedlist>
<listitem>
<para>The default formatting string has 12 fixed characters
("Shorewall" and three colons).</para>
</listitem>
<listitem>
<para>The longest of the standard dispositions are ACCEPT and
REJECT which have 6 characters each.</para>
</listitem>
<listitem>
<para>The canonical name for the chain containing the rules
for traffic going from zone 1 to zone 2 is "&lt;zone
1&gt;2&lt;zone 2&gt;".</para>
</listitem>
<listitem>
<para>So if M is the maximum zone name length, such chains can
have length 2*M + 1.</para>
<simplelist>
<member>12 + 6 + 2*M + 1 = 29 which reduces to</member>
<member>2*M = 29 - 12 - 6 - 1 = 10 or</member>
<member>M = 5</member>
</simplelist>
</listitem>
</itemizedlist>
</blockquote>
<para>The order in which Shorewall matches addresses from packets to
zones is determined by the order of zone declarations. Where a zone
is nested in one or more other zones, you may either ensure that the
nested zone precedes its parents in this file, or you may follow the
(sub)zone name by ":" and a comma-separated list of the parent
zones. The parent zones must have been declared in earlier records
in this file. See <ulink
url="shorewall-nesting.html">shorewall-nesting</ulink>(5) for
additional information.</para>
<para>Example:</para>
<programlisting>#ZONE TYPE OPTIONS IN OPTIONS OUT OPTIONS
a ipv4
b ipv4
c:a,b ipv4</programlisting>
<para>Currently, Shorewall uses this information to reorder the zone
list so that parent zones appear after their subzones in the list.
The IMPLICIT_CONTINUE option in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5) can also create
implicit CONTINUE policies to/from the subzone.</para>
<para>In the future, Shorewall may make additional use of nesting
information.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">TYPE</emphasis></term>
<listitem>
<variablelist>
<varlistentry>
<term><emphasis role="bold">ipv4</emphasis></term>
<listitem>
<para>This is the standard Shorewall zone type and is the
default if you leave this column empty or if you enter "-" in
the column. Communication with some zone hosts may be
encrypted. Encrypted hosts are designated using the
'ipsec'option in <ulink
url="shorewall-hosts.html">shorewall-hosts</ulink>(5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">ipsec</emphasis></term>
<listitem>
<para>Communication with all zone hosts is encrypted. Your
kernel and iptables must include policy match support.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">firewall</emphasis></term>
<listitem>
<para>Designates the firewall itself. You must have exactly
one 'firewall' zone. No options are permitted with a
'firewall' zone. The name that you enter in the ZONE column
will be stored in the shell variable $FW which you may use in
other configuration files to designate the firewall
zone.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>bport (or bport4)</term>
<listitem>
<para>(Shorewall-perl only) The zone is associated with one or
more ports on a single bridge.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">OPTIONS, IN OPTIONS and OUT
OPTIONS</emphasis> - [<emphasis>option</emphasis>[<emphasis
role="bold">,</emphasis><emphasis>option</emphasis>]...]</term>
<listitem>
<para>A comma-separated list of options. With the exception of the
<option>mss</option> option, these only apply to TYPE
<option>ipsec</option> zones.</para>
<variablelist>
<varlistentry>
<term><emphasis
role="bold">reqid=</emphasis><emphasis>number</emphasis></term>
<listitem>
<para>where <emphasis>number</emphasis> is specified using
setkey(8) using the 'unique:<emphasis>number</emphasis> option
for the SPD level.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">spi=</emphasis>&lt;number&gt;</term>
<listitem>
<para>where <emphasis>number</emphasis> is the SPI of the SA
used to encrypt/decrypt packets.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">proto=</emphasis><emphasis
role="bold">ah</emphasis>|<emphasis
role="bold">esp</emphasis>|<emphasis
role="bold">ipcomp</emphasis></term>
<listitem>
<para>IPSEC Encapsulation Protocol</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">mss=</emphasis><emphasis>number</emphasis></term>
<listitem>
<para>sets the MSS field in TCP packets. If you supply this
option, you should also set FASTACCEPT=No in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5) to insure
that both the SYN and SYN,ACK packets have their MSS field
adjusted.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">mode=</emphasis><emphasis
role="bold">transport</emphasis>|<emphasis
role="bold">tunnel</emphasis></term>
<listitem>
<para>IPSEC mode</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">tunnel-src=</emphasis><emphasis>address</emphasis>[/<emphasis>mask</emphasis>]</term>
<listitem>
<para>only available with mode=tunnel</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">tunnel-dst=</emphasis><emphasis>address</emphasis>[/<emphasis>mask</emphasis>]</term>
<listitem>
<para>only available with mode=tunnel</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">strict</emphasis></term>
<listitem>
<para>Means that packets must match all rules.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">next</emphasis></term>
<listitem>
<para>Separates rules; can only be used with strict</para>
</listitem>
</varlistentry>
</variablelist>
<para>The options in the OPTIONS column are applied to both incoming
and outgoing traffic. The IN OPTIONS are applied to incoming traffic
(in addition to OPTIONS) and the OUT OPTIONS are applied to outgoing
traffic.</para>
<para>If you wish to leave a column empty but need to make an entry
in a following column, use "-".</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>FILES</title>
<para>/etc/shorewall/zones</para>
</refsect1>
<refsect1>
<title>See ALSO</title>
<para><ulink
url="http://www.shorewall.net/Multiple_Zones.html">http://www.shorewall.net/Multiple_Zones.html</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-nesting(8), 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.conf(5),
shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5),
shorewall-tos(5), shorewall-tunnels(5)</para>
</refsect1>
</refentry>