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100 lines
3.5 KiB
XML
100 lines
3.5 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
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"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
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<article>
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<articleinfo>
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<title>ICMP Echo-request (Ping)</title>
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<authorgroup>
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<author>
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<firstname>Tom</firstname>
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<surname>Eastep</surname>
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</author>
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</authorgroup>
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<pubdate><?dbtimestamp format="Y/m/d"?></pubdate>
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<copyright>
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<year>2001-2005</year>
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<holder>Thomas M. Eastep</holder>
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</copyright>
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<legalnotice>
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<para>Permission is granted to copy, distribute and/or modify this
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document under the terms of the GNU Free Documentation License, Version
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1.2 or any later version published by the Free Software Foundation; with
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no Invariant Sections, with no Front-Cover, and with no Back-Cover
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Texts. A copy of the license is included in the section entitled
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<quote><ulink url="GnuCopyright.htm">GNU Free Documentation
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License</ulink></quote>.</para>
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</legalnotice>
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</articleinfo>
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<caution>
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<para><emphasis role="bold">This article applies to Shorewall 3.0 and
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later. If you are running a version of Shorewall earlier than Shorewall
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3.0.0 then please see the documentation for that
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release.</emphasis></para>
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</caution>
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<note>
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<para>Enabling <quote>ping</quote> will also enable ICMP-based
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<emphasis>traceroute</emphasis>. For UDP-based traceroute, see the <ulink
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url="ports.htm">port information page</ulink>.</para>
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</note>
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<section id="Ping">
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<title>'Ping' Management</title>
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<para>In Shorewall , ICMP echo-requests are treated just like any other
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connection request.</para>
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<para>In order to accept ping requests from zone z1 to zone z2 where the
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policy for z1 to z2 is not ACCEPT, you need a rule in
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<filename>/etc/shorewall/rules</filename> of the form:</para>
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<programlisting>#ACTION SOURCE DEST PROTO DPORT
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Ping(ACCEPT) z1 z2</programlisting>
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<example id="Example1">
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<title>Ping from local zone to firewall</title>
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<para>To permit ping from the local zone to the firewall:</para>
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<programlisting>#ACTION SOURCE DEST PROTO DPORT
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Ping(ACCEPT) loc $FW</programlisting>
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</example>
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<para>If you would like to accept <quote>ping</quote> by default even when
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the relevant policy is DROP or REJECT, copy
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<filename>/usr/share/shorewall/action.Drop</filename> or
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<filename>/usr/share shorewall/action.Reject</filename> respectively to
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<filename class="directory">/etc/shorewall</filename> and simply add this
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line to the copy:</para>
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<programlisting>Ping(ACCEPT)</programlisting>
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<para>With that rule in place, if you want to ignore <quote>ping</quote>
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from z1 to z2 then you need a rule of the form:</para>
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<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
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Ping(DROP) z1 z2</programlisting>
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<example id="Example2">
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<title>Silently drop pings from the Internet</title>
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<para>To drop ping from the Internet, you would need this rule in
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<filename>/etc/shorewall/rules</filename>:</para>
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<programlisting>#ACTION SOURCE DEST PROTO DEST PORT(S)
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Ping(DROP) net $FW</programlisting>
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</example>
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<para>Note that the above rule may be used without changing the action
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files to prevent your log from being flooded by messages generated from
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remote pinging.</para>
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</section>
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</article>
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