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Add 'Limit' target example

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git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@3124 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
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teastep 2005-12-06 21:29:53 +00:00
parent 88784dc6a0
commit a11655b27b
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Shorewall-docs2/PortKnocking.xml
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@ -185,5 +185,63 @@ SSHLimit net loc:192.168.1.5 tcp 22 -
</note>
</listitem>
</orderedlist>
<para>The above can be generalized into a flexible 'Limit' target.</para>
<orderedlist>
<listitem>
<para>Add an action named Limit. Leave the action.Limit file
empty.</para>
</listitem>
<listitem>
<para>Create /etc/shorewall/Limit with the following contents:</para>
<programlisting>set -- $(separate_list $TAG)
run_iptables -A $CHAIN -m recent --name $1 --set
if [ -n "$LEVEL" ]; then
log_rule_limit $LEVEL $CHAIN SSHLimit REJECT "" "" -A -m recent --name $1 --update --seconds $3 --hitcount $(( $2 + 1 ))
fi
run_iptables -A $CHAIN -m recent --update --name $1 --seconds $3 --hitcount $(( $2 + 1 )) -j reject
run_iptables -A $CHAIN -j ACCEPT</programlisting>
</listitem>
</orderedlist>
<para>Now if you want to limit the number of connections to port 22 to
3/munute from individual internet hosts to the filrewall, you can add this
rule:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
Limit:none:SSHA,3,60 net $FW tcp 22</programlisting>
<para>If you want rejected connections to be logged at the info level, use
this rule instead:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
Limit:info:SSHA,3,60 net $FW tcp 22</programlisting>
<para>As you can see, you pass four pieces of information to the Limit
action:</para>
<itemizedlist>
<listitem>
<para>The log level. If you don't want to log, specify "none".</para>
</listitem>
<listitem>
<para>The name of the recent set that you want to use ("SSHA" in this
example).</para>
</listitem>
<listitem>
<para>The maximum number of connections to accept (3 in this
example).</para>
</listitem>
<listitem>
<para>The number of seconds over which you are willing to accept that
many connections (60 in this example).</para>
</listitem>
</itemizedlist>
</section>
</article>