shorewall_code/Shorewall-docs/User_defined_Actions.xml
teastep afee989ee5 Shorewall 1.4.10
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@1099 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
2004-01-31 03:24:02 +00:00

185 lines
7.4 KiB
XML
Executable File

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<article>
<!--$Id$-->
<articleinfo>
<title>User-defined Actions</title>
<authorgroup>
<author>
<firstname>Tom</firstname>
<surname>Eastep</surname>
</author>
</authorgroup>
<pubdate>2003-01-29</pubdate>
<copyright>
<year>2003-2004</year>
<holder>Thomas M. Eastep</holder>
</copyright>
<legalnotice>
<para>Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version
1.2 or any later version published by the Free Software Foundation; with
no Invariant Sections, with no Front-Cover, and with no Back-Cover
Texts. A copy of the license is included in the section entitled
<quote><ulink url="GnuCopyright.htm">GNU Free Documentation License</ulink></quote>.</para>
</legalnotice>
</articleinfo>
<para>Prior to Shorewall version 1.4.9, rules in <filename>/etc/shorewall/rules</filename>
were limited to those defined by Netfilter (ACCEPT, DROP, REJECT, etc.).
Beginning with Shorewall version 1.4.9, users may use sequences of these
elementary operations to define more complex actions.</para>
<para>To define a new action:</para>
<orderedlist>
<listitem>
<para>Add a line to <filename><filename>/etc/shorewall/actions</filename></filename>
that names your new action. Action names must be valid shell variable
names as well as valid Netfilter chain names. It is recommended that the
name you select for a new action begins with with a capital letter; that
way, the name won&#39;t conflict with a Shorewall-defined chain name.</para>
</listitem>
<listitem>
<para>Once you have defined your new action name (ActionName), then copy
/etc/shorewall/action.template to <filename>/etc/shorewall/action.ActionName</filename>
(for example, if your new action name is <quote>Foo</quote> then copy
<filename>/etc/shorewall/action.template</filename> to
<filename>/etc/shorewall/action.Foo</filename>).</para>
</listitem>
<listitem>
<para>Now modify the new file to define the new action.</para>
</listitem>
</orderedlist>
<para>Columns in the action.template file are as follows:</para>
<itemizedlist>
<listitem>
<para>TARGET - Must be ACCEPT, DROP, REJECT, LOG, QUEUE or
&#60;action&#62; where &#60;action&#62; is a previously-defined action
(that is, it must precede the action being defined in this file in your
<filename>/etc/shorewall/actions</filename> file). The TARGET may
optionally be followed by a colon (<quote>:</quote>) and a syslog log
level (e.g, REJECT:info or ACCEPT:debugging). This causes the packet to
be logged at the specified level. You may also specify ULOG (must be in
upper case) as a log level.This will log to the ULOG target for routing
to a separate log through use of ulogd (<ulink
url="http://www.gnumonks.org/projects/ulogd">http://www.gnumonks.org/projects/ulogd</ulink>).</para>
</listitem>
<listitem>
<para>SOURCE - Source hosts to which the rule applies. A comma-separated
list of subnets and/or hosts. Hosts may be specified by IP or MAC
address; mac addresses must begin with <quote>~</quote> and must use
<quote>-</quote> as a separator.</para>
<para>Alternatively, clients may be specified by interface name. For
example, eth1 specifies a client that communicates with the firewall
system through eth1. This may be optionally followed by another colon (<quote>:</quote>)
and an IP/MAC/subnet address as described above (e.g.,
eth1:192.168.1.5).</para>
</listitem>
<listitem>
<para>DEST - Location of Server. Same as above with the exception that
MAC addresses are not allowed.</para>
<para>Unlike in the SOURCE column, you may specify a range of up to 256
IP addresses using the syntax &#60;<emphasis>first ip</emphasis>&#62;-&#60;<emphasis>last
ip</emphasis>&#62;.</para>
</listitem>
<listitem>
<para>PROTO - Protocol - Must be <quote>tcp</quote>, <quote>udp</quote>,
<quote>icmp</quote>, a number, or <quote>all</quote>.</para>
</listitem>
<listitem>
<para>DEST PORT(S) - Destination Ports. A comma-separated list of Port
names (from <filename>/etc/services</filename>), port numbers or port
ranges; if the protocol is <quote>icmp</quote>, this column is
interpreted as the destination icmp-type(s).</para>
<para>A port range is expressed as &#60;<emphasis>low port</emphasis>&#62;:&#60;<emphasis>high
port</emphasis>&#62;.</para>
<para>This column is ignored if PROTOCOL = all but must be entered if
any of the following ields are supplied. In that case, it is suggested
that this field contain <quote>-</quote>.</para>
<para>If your kernel contains multi-port match support, then only a
single Netfilter rule will be generated if in this list and in the
CLIENT PORT(S) list below:</para>
<orderedlist>
<listitem>
<para>There are 15 or less ports listed.</para>
</listitem>
<listitem>
<para>No port ranges are included.</para>
</listitem>
</orderedlist>
<para>Otherwise, a separate rule will be generated for each port.</para>
</listitem>
<listitem>
<para>SOURCE PORT(S) - Port(s) used by the client. If omitted, any
source port is acceptable. Specified as a comma-separated list of port
names, port numbers or port ranges.</para>
<para>If you don&#39;t want to restrict client ports but need to specify
an ADDRESS in the next column, then place &#34;-&#34; in this column.</para>
<para>If your kernel contains multi-port match support, then only a
single Netfilter rule will be generated if in this list and in the DEST
PORT(S) list above:</para>
<orderedlist>
<listitem>
<para>There are 15 or less ports listed.</para>
</listitem>
<listitem>
<para>No port ranges are included.</para>
</listitem>
</orderedlist>
<para>Otherwise, a separate rule will be generated for each port.</para>
</listitem>
<listitem>
<para>RATE LIMIT - You may rate-limit the rule by placing a value in
this column:</para>
<para><programlisting> &#60;<emphasis>rate</emphasis>&#62;/&#60;<emphasis>interval</emphasis>&#62;[:&#60;<emphasis>burst</emphasis>&#62;]</programlisting>where
&#60;<emphasis>rate</emphasis>&#62; is the number of connections per
&#60;<emphasis>interval</emphasis>&#62; (<quote>sec</quote> or
<quote>min</quote>) and &#60;<emphasis>burst</emphasis>&#62; is the
largest burst permitted. If no &#60;<emphasis>burst</emphasis>&#62; is
given, a value of 5 is assumed. There may be no whitespace embedded in
the specification.</para>
<para><programlisting> Example: 10/sec:20</programlisting></para>
</listitem>
</itemizedlist>
<para>Example:</para>
<para><filename>/etc/shorewall/actions</filename>:</para>
<para><programlisting> LogAndAccept</programlisting><phrase><filename>/etc/shorewall/action.LogAndAccept</filename></phrase><programlisting> LOG:info
ACCEPT</programlisting></para>
</article>