shorewall_code/Shorewall/manpages/shorewall-policy.xml
Tuomo Soini be924ff765
Fix http links to point to current project website
Also removes deprecated Shorewall6/configfiles/masq

Signed-off-by: Tuomo Soini <tis@foobar.fi>
Signed-off-by: Tom Eastep <teastep@shorewall.net>
2020-03-27 14:24:37 -07:00

454 lines
19 KiB
XML

<?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-policy</refentrytitle>
<manvolnum>5</manvolnum>
<refmiscinfo>Configuration Files</refmiscinfo>
</refmeta>
<refnamediv>
<refname>policy</refname>
<refpurpose>Shorewall policy file</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>/etc/shorewall[6]/policy</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>This file defines the high-level policy for connections between
zones defined in <ulink
url="shorewall-zones.html">shorewall-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 <ulink
url="shorewall-blrules.html">shorewall-blrules</ulink>(5) or
<ulink url="shorewall-rules.html">shorewall-rules</ulink>(5)
files. For each source/destination pair, the file is processed in order
until a match is found ("all" will match any source or
destination).</para>
</important>
<important>
<para>Intra-zone policies are pre-defined</para>
<para>For $FW and for all of the zones defined in <ulink
url="shorewall-zones.html">shorewall-zones</ulink>(5), the
POLICY for connections from the zone to itself is ACCEPT (with no
logging or TCP connection rate limiting) but may be overridden by an
entry in this file. The overriding entry must be explicit (specifying
the zone name in both SOURCE and DEST) or it must use "all+" (Shorewall
4.5.17 or later).</para>
<para>Similarly, if you have IMPLICIT_CONTINUE=Yes in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5), then the
implicit policy to/from any sub-zone is CONTINUE. These implicit
CONTINUE policies may also be overridden by an explicit entry in this
file.</para>
</important>
<para>The columns in the file are as follows (where the column name is
followed by a different name in parentheses, the different name is used in
the alternate specification syntax).</para>
<variablelist>
<varlistentry>
<term><emphasis role="bold">SOURCE</emphasis> -
<emphasis>zone</emphasis>[,...[+]]|<emphasis
role="bold">$FW</emphasis>|<emphasis
role="bold">all[+][!<replaceable>ezone</replaceable>[,...]]</emphasis></term>
<listitem>
<para>Source zone. Must be the name of a zone defined in <ulink
url="shorewall-zones.html">shorewall-zones</ulink>(5),
$FW, "all" or "all+".</para>
<para>Support for <emphasis role="bold">all+</emphasis> was added in
Shorewall 4.5.17. <emphasis role="bold">all</emphasis> does not
override the implicit intra-zone ACCEPT policy while <emphasis
role="bold">all+</emphasis> does.</para>
<para>Beginning with Shorewall 5.0.12, multiple zones may be listed
separated by commas. As above, if '+' is specified after two or more
zone names, then the policy overrides the implicit intra-zone ACCEPT
policy if the same <replaceable>zone</replaceable> appears in both
the SOURCE and DEST columns.</para>
<para>Beginning with Shorewall 5.2.3, a comma-separated list of
excluded zones preceded by "!" may follow <emphasis
role="bold">all</emphasis> or <emphasis
role="bold">all+.</emphasis></para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">DEST</emphasis> -
<emphasis>zone</emphasis>[,...[+]]|<emphasis
role="bold">$FW</emphasis>|all[+][!<replaceable>ezone</replaceable>[,...]]</term>
<listitem>
<para>Destination zone. Must be the name of a zone defined in <ulink
url="shorewall-zones.html">shorewall-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>
<para>Beginning with Shorewall 5.0.12, multiple zones may be listed
separated by commas. As above, if '+' is specified after two or more
zone names, then the policy overrides the implicit intra-zone ACCEPT
policy if the same <replaceable>zone</replaceable> appears in both
the SOURCE and DEST columns.</para>
<para>Beginning with Shorewall 5.2.3, a comma-separated list of
excluded zones preceded by "!" may follow <emphasis
role="bold">all</emphasis> or <emphasis
role="bold">all+</emphasis>.</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">BLACKLIST</emphasis>|<emphasis
role="bold">CONTINUE</emphasis>|<emphasis
role="bold">QUEUE</emphasis>|<emphasis
role="bold">NFQUEUE</emphasis>[([<replaceable>queuenumber</replaceable>1[:<replaceable>queuenumber2</replaceable>[c]][,bypass]]|bypass)]|<emphasis
role="bold">NONE</emphasis>}[<emphasis
role="bold">:</emphasis>{[+]<emphasis>policy-action</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="shorewall.conf.html">shorewall.conf</ulink>(5) to
be omitted for this policy.</para>
</listitem>
<listitem>
<para>The name of an action with optional parameters enclosed in
parentheses. 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>Beginning with Shorewall 5.1.2, multiple
<replaceable>action</replaceable>[:<replaceable>level</replaceable>]
specification may be listeded, separated by commas. The actions are
invoked in the order listed. Also beginning with Shorewall 5.1.2,
the policy-action list can be prefixed with a plus sign ("+")
indicating that the listed actions are in addition to those listed
in the related _DEFAULT setting in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5).</para>
<para>Possible policies 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">BLACKLIST</emphasis></term>
<listitem>
<para>Added in Shorewall 5.1.1 and requires that the
DYNAMIC_BLACKLIST setting in <ulink
url="shorewall.conf.html">shorewall.conf</ulink>(5)
specifies ipset-based dynamic blacklisting. The SOURCE IP
address is added to the blacklist ipset and the connection
request is ignored.</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. Beginning with
Shorewall 5.1.0, queuenumber2 may be followed by the letter
'c' to indicate that the CPU ID will be used as an index to
map packets to the queues. The idea is that you can improve
performance if there's a queue per CPU. Requires the NFQUEUE
CPU Fanout capability in your kernel and iptables.</para>
<para>Beginning with Shorewall 4.6.10, the keyword <emphasis
role="bold">bypass</emphasis> can be given. By default, if no
userspace program is listening on an NFQUEUE, then all packets
that are to be queued are dropped. When this option is used,
the NFQUEUE rule behaves like ACCEPT instead.</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="shorewall-nesting.html">shorewall-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. 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>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis role="bold">LOGLEVEL</emphasis> (loglevel) -
[<emphasis>log-level</emphasis>|<emphasis
role="bold">ULOG|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 ULOG or NFLOG (must be in upper case).
This will log to the ULOG or 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 logging, see <ulink
url="../shorewall_logging.html">shorewall-logging(5)</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">RATE</emphasis> (rate) -
[-|<replaceable>limit</replaceable>]</term>
<listitem>
<para>where limit is one of:</para>
<simplelist>
<member>[<emphasis role="bold">-</emphasis>|[{<emphasis
role="bold">s</emphasis>|<emphasis
role="bold">d</emphasis>}[/<replaceable>vlsm</replaceable>]:[[<replaceable>name</replaceable>][(ht-buckets,ht-max)]:]]]<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. Beginning with Shorewall 5.2.1, the <emphasis
role="bold">s</emphasis> or <emphasis role="bold">d</emphasis> may
be followed by a slash ("/") and an integer
<replaceable>vlsm</replaceable>. When a
<replaceable>vlsm</replaceable> is specified, all source or
destination addresses encountered will be grouped according to the
given prefix length and the so-created subnet will be subject to the
rate limit.</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>
<para>Beginning with Shorewall 5.2.1, the table name, if any, may be
followed by two integers separated by commas and enclosed in
parentheses. The first integer
(<replaceable>ht-buckets</replaceable>) specifies the number of
buckets in the generated hash table. The second integer
(<replaceable>ht-max</replaceable>) specifies the maximum number of
entries in the hash table.</para>
<para>Example: <emphasis
role="bold">s:client(1024,65536):10/sec</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/shorewall/policy</para>
<para>/etc/shorewall6/policy</para>
</refsect1>
<refsect1>
<title>See ALSO</title>
<para><ulink
url="../configuration_file_basics.htm#Pairs">https://shorewall.org/configuration_file_basics.htm#Pairs</ulink></para>
<para>shorewall(8)</para>
</refsect1>
</refentry>