shorewall_code/Shorewall/manpages/shorewall-zones.xml
Matt Darfeuille 53495ec0a8
Point exclusively to shorewall.org
Signed-off-by: Matt Darfeuille <matdarf@gmail.com>
Signed-off-by: Tom Eastep <teastep@shorewall.net>
2019-03-25 11:35:00 -07:00

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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>
<refmiscinfo>Configuration Files</refmiscinfo>
</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 (where the column name is
followed by a different name in parentheses, the different name is used in
the alternate specification syntax).</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>. Must start with a
letter and consist of letters, digits or '_'. The names "all",
"none", "any", "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="/manpages/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="/manpages/shorewall.conf.html">shorewall.conf</ulink> (5),
the legacy 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 "Shorewall:%s:%s:" 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;" or "&lt;zone 1&gt;-&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>
<para>In Shorewall 5.1.0, the LOGFORMAT in the default and sample
shorewall.conf files was changed to "%s:%s ".</para>
<itemizedlist>
<listitem>
<para>That formatting string has 2 fixed characters (":" and a
space).</para>
</listitem>
<listitem>
<para>So the maximum zone name length M is calculated
as:</para>
<simplelist>
<member>2 + 6 + 2*M + 1 = 29</member>
<member>2M = 29 - 2 - 6 - 1 = 20</member>
<member>M = 10</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="/manpages/shorewall-nesting.html">shorewall-nesting</ulink>(5)
for additional information.</para>
<para>Example:</para>
<programlisting>#ZONE TYPE OPTIONS IN OPTIONS OUT OPTIONS
a ip
b ip
c:a,b ip</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="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5) can
also create implicit CONTINUE policies to/from the subzone.</para>
<para>Where an <emphasis role="bold">ipsec</emphasis> zone is
explicitly included as a child of an <emphasis
role="bold">ip</emphasis> zone, the ruleset allows CONTINUE policies
(explicit or implicit) to work as expected.</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">ip</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="/manpages/shorewall-hosts.html">shorewall-hosts</ulink>(5).
For clarity, this zone type may be specified as
<option>ipv4</option> in IPv4 configurations and
<option>ipv6</option> in IPv6 configurations.</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. For
clarity, this zone type may be specified as
<option>ipsec4</option> in IPv4 configurations and
<option>ipsec6</option> in IPv6 configurations.</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><emphasis role="bold">bport</emphasis></term>
<listitem>
<para>The zone is associated with one or more ports on a
single bridge. For clarity, this zone type may be specified as
<option>bport4</option> in IPv4 configurations and
<option>bport6</option> in IPv6 configurations.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">vserver</emphasis></term>
<listitem>
<para>Added in Shorewall 4.4.11 Beta 2 - A zone composed of
Linux-vserver guests. The zone contents must be defined in
<ulink
url="/manpages/shorewall-hosts.html">shorewall-hosts</ulink>
(5).</para>
<para>Vserver zones are implicitly handled as subzones of the
firewall zone.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">loopback</emphasis></term>
<listitem>
<para>Added in Shorewall 4.5.17.</para>
<para>Normally, Shorewall treats the loopback interface (lo)
in the following way:</para>
<itemizedlist>
<listitem>
<para>By default, all traffic through the interface is
ACCEPTed.</para>
</listitem>
<listitem>
<para>If a $FW -&gt; $FW policy is defined or $FW -&gt;
$FW rules are defined, they are placed in a chain named
${FW}2${F2} or ${FW}-${FW} (e.g., 'fw2fw' or 'fw-fw' )
depending on the ZONE2ZONE setting in <ulink
url="/manpages/shorewall.conf.html">shorewall.conf</ulink>(5).</para>
</listitem>
<listitem>
<para>$FW -&gt; $FW traffic is only filtered in the OUTPUT
chain.</para>
</listitem>
</itemizedlist>
<para>By defining a <emphasis role="bold">loopback</emphasis>
zone and associating it with the loopback interface in
shorewall-interfaces(5), you can effect a slightly different
model. Suppose that the <emphasis
role="bold">loopback</emphasis> zone name is 'local';
then:</para>
<itemizedlist>
<listitem>
<para>Both $FW -&gt; local and local -&gt; $FW chains are
created.</para>
</listitem>
<listitem>
<para>The $FW -&gt; local and local -&gt; $FW policies may
be different.</para>
</listitem>
<listitem>
<para>Both $FW -&gt; local and local -&gt; $FW rules may
be specified.</para>
</listitem>
</itemizedlist>
<para>Rules to/from the <emphasis
role="bold">loopback</emphasis> zone and any zone other than
the firewall zone are ignored with a warning.</para>
<para><emphasis role="bold">loopback</emphasis> zones may be
nested within other <emphasis role="bold">loopback</emphasis>
zones.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>local</term>
<listitem>
<para>Added in Shorewall 4.5.17. <emphasis
role="bold">local</emphasis> is the same as <emphasis
role="bold">ipv4</emphasis> with the exception that the zone
is only accessible from the <emphasis
role="bold">firewall</emphasis> and <emphasis
role="bold">vserver</emphasis> zones.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">OPTIONS, IN OPTIONS and OUT
OPTIONS</emphasis> (options, in_options, out_options) -
[<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> and <option>blacklist</option> options, these
only apply to TYPE <option>ipsec</option> zones.</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">dynamic_shared</emphasis></term>
<listitem>
<para>Added in Shorewall 4.5.9. May only be specified in the
OPTIONS column and indicates that only a single ipset should
be created for this zone if it has multiple dynamic entries in
<ulink
url="/manpages/shorewall-hosts.html">shorewall-hosts</ulink>(5).
Without this option, a separate ipset is created for each
interface.</para>
</listitem>
</varlistentry>
<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="/manpages/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>
<para>/etc/shorewall6/zones</para>
</refsect1>
<refsect1>
<title>See ALSO</title>
<para><ulink
url="/Multiple_Zones.html">http://www.shorewall.org/Multiple_Zones.html</ulink>.</para>
<para><ulink
url="/configuration_file_basics.htm#Pairs">http://www.shorewall.org/configuration_file_basics.htm#Pairs</ulink></para>
<para>shorewall(8)</para>
</refsect1>
</refentry>