shorewall_code/manpages/shorewall-policy.xml
2006-11-20 17:52:52 +00:00

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<?xml version="1.0" encoding="UTF-8"?>
<refentry>
<refmeta>
<refentrytitle>shorewall-policy</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>policy</refname>
<refpurpose>Shorewall policy file</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>/etc/shorewall/policy</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>This file defines the high-level policy for connections between
zones defined in /etc/shorewall/zones.</para>
<important>
<para>The order of entries in this file is important</para>
<para>This file determines what to do with a new connection request if
we don't get a match from the /etc/shorewall/rules file . For each
source/destination pair, the file is processed in order until a match is
found ("all" will match any client or server).</para>
</important>
<important>
<para>Intra-zone policies are pre-defined</para>
<para>For $FW and for all of the zones defined in /etc/shorewall/zones,
the POLICY for connections from the zone to itself is ACCEPT (with no
logging or TCP connection rate limiting but may be overridden by an
entry in this file. The overriding entry must be explicit (cannot use
"all" in the SOURCE or DEST).</para>
<para>Similarly, if you have IMPLICIT_CONTINUE=Yes in shorewall.conf,
then the implicit policy to/from any sub-zone is CONTINUE. These
implicit CONTINUE policies may also be overridden by an explicit entry
in this file.</para>
</important>
<para>The columns in the file are as follows.</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">SOURCE</emphasis></term>
<listitem>
<para>Source zone. Must be the name of a zone defined in
/etc/shorewall/zones, $FW or "all".</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DEST</emphasis></term>
<listitem>
<para>Destination zone. Must be the name of a zone defined in
/etc/shorewall/zones, $FW or "all"</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">POLICY</emphasis></term>
<listitem>
<para>Policy if no match from the rules file is found. Must be
"ACCEPT", "DROP", "REJECT", "CONTINUE" or "NONE".</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">ACCEPT</emphasis></term>
<listitem>
<para>Accept the connection.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DROP</emphasis></term>
<listitem>
<para>Ignore the connection request.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">REJECT</emphasis></term>
<listitem>
<para>For TCP, send RST. For all other, send an "unreachable"
ICMP.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">CONTINUE</emphasis></term>
<listitem>
<para>Pass the connection request past any other rules that it
might also match (where the source or destination zone in
those rules is a superset of the SOURCE or DEST in this
policy).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">NONE</emphasis></term>
<listitem>
<para>Assume that there will never be any packets from this
SOURCE to this DEST. Shorewall will not create any
infrastructure to handle such packets and you may not have any
rules with this SOURCE and DEST in the /etc/shorewall/rules
file. If such a packet <emphasis role="bold">is</emphasis>
received, the result is undefined. NONE may not be used if the
SOURCE or DEST columns contain the firewall zone ($FW) or
"all".</para>
</listitem>
</varlistentry>
</variablelist>
<para>If the policy is DROP or REJECT then the policy may be
followed by ":" and one of the following:</para>
<orderedlist numeration="loweralpha">
<listitem>
<para>The word "None" or "none". This causes any default action
defined in /etc/shorewall/shorewall.conf to be omitted for this
policy.</para>
</listitem>
<listitem>
<para>The name of an action (requires that USE_ACTIONS=Yes in
shorewall.conf). That action will be invoked before the policy
is enforced.</para>
</listitem>
<listitem>
<para>The name of a macro. The rules in that macro will be
applied before the policy is enforced. This does not require
USE_ACTIONS=Yes.</para>
</listitem>
</orderedlist>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">LOG LEVEL</emphasis> (Optional)</term>
<listitem>
<para>If supplied, each connection handled under the default POLICY
is logged at that level. If not supplied, no log message is
generated. See syslog.conf(5) for a description of log
levels.</para>
<para>You may also specify ULOG (must be in upper case). This will
log to the ULOG target and will send to a separate log through use
of ulogd (http://www.gnumonks.org/projects/ulogd).</para>
<para>If you don't want to log but need to specify the following
column, place "-" here.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">BURST:LIMIT</emphasis></term>
<listitem>
<para>If passed, specifies the maximum TCP connection rate and the
size of an acceptable burst. If not specified, TCP connections are
not limited.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Example</title>
<orderedlist numeration="loweralpha">
<listitem>
<para>All connections from the local network to the internet are
allowed</para>
</listitem>
<listitem>
<para>All connections from the internet are ignored but logged at
syslog level KERNEL.INFO.</para>
</listitem>
<listitem>
<para>All other connection requests are rejected and logged at level
KERNEL.INFO.</para>
</listitem>
</orderedlist>
<programlisting>#SOURCE DEST POLICY LOG BURST:LIMIT
# LEVEL
loc net ACCEPT
net all DROP info
#
# THE FOLLOWING POLICY MUST BE LAST
#
all all REJECT info</programlisting>
</refsect1>
<refsect1>
<title>FILES</title>
<para>/etc/shorewall/policy</para>
</refsect1>
<refsect1>
<title>See ALSO</title>
<para>http://shorewall.net/Documentation.htm#Policy</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-netmap(5), shorewall-params(5),
shorewall-policy(5), shorewall-providers(5), shorewall-proxyarp(5),
shorewall-route_routes(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),
shorewall-zones(5)</para>
</refsect1>
</refentry>