shorewall_code/Shorewall6/manpages/shorewall6-policy.xml

383 lines
16 KiB
XML
Raw Permalink Normal View History

<?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>shorewall6-policy</refentrytitle>
<manvolnum>5</manvolnum>
<refmiscinfo>Configuration Files</refmiscinfo>
</refmeta>
<refnamediv>
<refname>policy</refname>
<refpurpose>shorewall6 policy file</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>/etc/shorewall6/policy</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>This file defines the high-level policy for connections between
zones defined in <ulink
url="/manpages6/shorewall6-zones.html">shorewall6-zones</ulink>(5).</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/shorewall6/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 $FW and for all of the zones defined in /etc/shorewall6/zones,
the POLICY for connections from the zone to itself is ACCEPT (with no
logging or TCP connection rate limiting but may be overridden by an
entry in this file. The overriding entry must be explicit (specifying
the zone name on both SOURCE and DEST) or it must use "all+ or it must
use "all+" (Shorewall 4.5.17 or later).</para>
<para>Similarly, if you have IMPLICIT_CONTINUE=Yes in shorewall6.conf,
then the implicit policy to/from any sub-zone is CONTINUE. These
implicit CONTINUE policies may also be overridden by an explicit entry
in this file.</para>
</important>
<para>The columns in the file are as follows (where the column name is
followed by a different name in parentheses, the different name is used in
the alternate specification syntax).</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">SOURCE</emphasis> -
<emphasis>zone</emphasis>|<emphasis
role="bold">$FW</emphasis>|<emphasis
role="bold">all</emphasis>|<emphasis
role="bold">all+</emphasis></term>
<listitem>
<para>Source zone. Must be the name of a zone defined in <ulink
url="/manpages6/shorewall6-zones.html">shorewall6-zones</ulink>(5),
$FW, "all" or "all+".</para>
<para>Support for "all+" was added in Shorewall 4.5.17. "all" does
not override the implicit intra-zone ACCEPT policy while "all+"
does.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DEST</emphasis> -
<emphasis>zone</emphasis>|<emphasis
role="bold">$FW</emphasis>|<emphasis
role="bold">all</emphasis>|<emphasis
role="bold">all+</emphasis></term>
<listitem>
<para>Destination zone. Must be the name of a zone defined in <ulink
url="/manpages6/shorewall6-zones.html">shorewall6-zones</ulink>(5),
$FW, "all" or "all+". If the DEST is a bport zone, then the SOURCE
must be "all", "all+", another bport zone associated with the same
bridge, or it must be an ipv4 zone that is associated with only the
same bridge.</para>
<para>Support for "all+" was added in Shorewall 4.5.17. "all" does
not override the implicit intra-zone ACCEPT policy while "all+"
does.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">POLICY</emphasis> - {<emphasis
role="bold">ACCEPT</emphasis>|<emphasis
role="bold">DROP</emphasis>|<emphasis
role="bold">REJECT</emphasis>|<emphasis
role="bold">CONTINUE</emphasis>|<emphasis
role="bold">QUEUE</emphasis>|<emphasis
role="bold">NFQUEUE</emphasis>[(<emphasis>queuenumber1</emphasis>[:<replaceable>queuenumber2</replaceable>])]|<emphasis
role="bold">NONE</emphasis>}[<emphasis
role="bold">:</emphasis>{<emphasis>default-action-or-macro</emphasis>[:level]|<emphasis
role="bold">None</emphasis>}]</term>
<listitem>
<para>Policy if no match from the rules file is found.</para>
<para>If the policy is neither CONTINUE nor NONE 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 <ulink
url="/manpages6/shorewall6.conf.html">shorewall6.conf</ulink>(5)
to be omitted for this policy.</para>
</listitem>
<listitem>
<para>The name of an action. The action will be invoked before
the policy is enforced.</para>
</listitem>
</orderedlist>
<para>Actions can have parameters specified.</para>
<para>Beginning with Shorewall 4.5.10, the action name can be
followed optionally by a colon and a log level. The level will be
applied to each rule in the action or body that does not already
have a log level.</para>
<para>Possible actions are:</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">QUEUE</emphasis></term>
<listitem>
<para>Queue the request for a user-space application such as
Snort-inline.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">NFQUEUE</emphasis></term>
<listitem>
<para>Queue the request for a user-space application using the
nfnetlink_queue mechanism. If a
<replaceable>queuenumber1</replaceable> is not given, queue
zero (0) is assumed. Beginning with Shorewall 4.6.10, a second
queue number (queuenumber2) may be given. This specifies a
range of queues to use. Packets are then balanced across the
given queues. This is useful for multicore systems: start
multiple instances of the userspace program on queues x, x+1,
.. x+n and use "x:x+n". Packets belonging to the same
connection are put into the same nfqueue.</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). See <ulink
url="/manpages6/shorewall6-nesting.html">shorewall6-nesting</ulink>(5)
for additional information.</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. shorewall6 will not create any
infrastructure to handle such packets and you may not have any
rules with this SOURCE and DEST in the /etc/shorewall6/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>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">LOG LEVEL</emphasis> (loglevel) -
[<emphasis>log-level</emphasis>|<emphasis
role="bold">NFLOG</emphasis>]</term>
<listitem>
<para>Optional - 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 NFLOG (must be in upper case). This will
log to the NFLOG target and will send to a separate log through use
of ulogd (<ulink
url="http://www.netfilter.org/projects/ulogd/index.html">http://www.netfilter.org/projects/ulogd/index.html</ulink>).</para>
<para>For a description of log levels, see <ulink
url="/shorewall_logging.html.">http://www.shorewall.net/shorewall_logging.html.</ulink></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> (limit) -
[-|<replaceable>limit</replaceable>]</term>
<listitem>
<para>where limit is one of:</para>
<simplelist>
<member>[<emphasis
role="bold">-</emphasis>|[{<emphasis>s</emphasis>|<emphasis
role="bold">d</emphasis>}:[[<replaceable>name</replaceable>]:]]]<emphasis>rate</emphasis><emphasis
role="bold">/</emphasis>{<emphasis
role="bold">sec</emphasis>|<emphasis
role="bold">min</emphasis>|<emphasis
role="bold">hour</emphasis>|<emphasis
role="bold">day</emphasis>}[:<emphasis>burst</emphasis>]</member>
<member>[<replaceable>name</replaceable>1]:<emphasis>rate1</emphasis><emphasis
role="bold">/</emphasis>{<emphasis
role="bold">sec</emphasis>|<emphasis
role="bold">min</emphasis>|<emphasis
role="bold">hour</emphasis>|<emphasis
role="bold">day</emphasis>}[:<emphasis>burst1</emphasis>],[<replaceable>name</replaceable>2]:<emphasis>rate2</emphasis><emphasis
role="bold">/</emphasis>{<emphasis
role="bold">sec</emphasis>|<emphasis
role="bold">min</emphasis>|<emphasis
role="bold">hour</emphasis>|<emphasis
role="bold">day</emphasis>}[:<emphasis>burst2</emphasis>]</member>
</simplelist>
<para>If passed, specifies the maximum TCP connection
<emphasis>rate</emphasis> and the size of an acceptable
<emphasis>burst</emphasis>. If not specified, TCP connections are
not limited. If the <replaceable>burst</replaceable> parameter is
omitted, a value of 5 is assumed.</para>
<para>When <option>s:</option> or <option>d:</option> is specified,
the rate applies per source IP address or per destination IP address
respectively. The <replaceable>name</replaceable> may be chosen by
the user and specifies a hash table to be used to count matching
connections. If not give, the name <emphasis
role="bold">shorewall</emphasis> is assumed. Where more than one
POLICY or rule specifies the same name, the connections counts for
the policies are aggregated and the individual rates apply to the
aggregated count.</para>
<para>Beginning with Shorewall 4.6.5, two<replaceable>
limit</replaceable>s may be specified, separated by a comma. In this
case, the first limit (<replaceable>name1</replaceable>,
<replaceable>rate1</replaceable>, burst1) specifies the per-source
IP limit and the second limit specifies the per-destination IP
limit.</para>
<para>Example: <emphasis
role="bold">client:10/sec:20,:60/sec:100</emphasis></para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">CONNLIMIT</emphasis> -
<emphasis>limit</emphasis>[:<emphasis>mask</emphasis>]</term>
<listitem>
<para>May be used to limit the number of simultaneous connections
from each individual host to <replaceable>limit</replaceable>
connections. While the limit is only checked on connections to which
this policy could apply, the number of current connections is
calculated over all current connections from the SOURCE host. By
default, the limit is applied to each host individually but can be
made to apply to networks of hosts by specifying a
<replaceable>mask</replaceable>. The <replaceable>mask</replaceable>
specifies the width of a VLSM mask to be applied to the source
address; the number of current connections is then taken over all
hosts in the subnet
<replaceable>source-address</replaceable>/<replaceable>mask</replaceable>.</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/shorewall6/policy</para>
</refsect1>
<refsect1>
<title>See ALSO</title>
<para><ulink
url="/configuration_file_basics.htm#Pairs">http://www.shorewall.net/configuration_file_basics.htm#Pairs</ulink></para>
<para>shorewall6(8), shorewall6-accounting(5), shorewall6-actions(5),
shorewall6-blacklist(5), shorewall6-hosts(5), shorewall6-interfaces(5),
shorewall6-ipsec(5), shorewall6-maclist(5), shorewall6-masq(5),
shorewall6-nat(5), shorewall6-netmap(5),
2013-05-03 18:19:45 +02:00
shorewall6-netmap(5),shorewall6-params(5), shorewall6-policy(5),
shorewall6-providers(5), shorewall6-proxyarp(5), shorewall6-rtrules(5),
shorewall6-routestopped(5), shorewall6-rules(5), shorewall6.conf(5),
shorewall6-secmarks(5), shorewall6-tcclasses(5), shorewall6-tcdevices(5),
shorewall6-mangle(5), shorewall6-tos(5), shorewall6-tunnels(5),
shorewall6-zones(5)</para>
</refsect1>
</refentry>