Update ECN Documentation to reflect kernel bug

git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@1907 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
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teastep 2005-01-17 18:12:49 +00:00
parent 887467672c
commit b903703d7f

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@ -15,7 +15,7 @@
</author>
</authorgroup>
<pubdate>2003-03-28</pubdate>
<pubdate>2005-01-17</pubdate>
<copyright>
<year>2001</year>
@ -24,6 +24,8 @@
<year>2003</year>
<year>2005</year>
<holder>Thomas M. Eastep</holder>
</copyright>
@ -33,17 +35,24 @@
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>
<quote><ulink url="GnuCopyright.htm">GNU Free Documentation
License</ulink></quote>.</para>
</legalnotice>
</articleinfo>
<warning>
<para>2006-01-17. The ECN Netfilter target in recent 2.6 Linux Kernels is
broken. Symptoms are that you will be unable to establish a TCP connection
to hosts defined in the /etc/shorewall/ecn file.</para>
</warning>
<section>
<title>Explicit Congestion Notification (ECN)</title>
<para>Explicit Congestion Notification (ECN) is described in RFC 3168 and
is a proposed internet standard. Unfortunately, not all sites support ECN
and when a TCP connection offering ECN is sent to sites that don&#39;t
support it, the result is often that the connection request is ignored.</para>
and when a TCP connection offering ECN is sent to sites that don't support
it, the result is often that the connection request is ignored.</para>
<para>To allow ECN to be used, Shorewall allows you to enable ECN on your
Linux systems then disable it in your firewall when the destination
@ -51,7 +60,7 @@
<para>You enable ECN by</para>
<programlisting>echo 1 &#62; /proc/sys/net/ipv4/tcp_ecn</programlisting>
<programlisting>echo 1 &gt; /proc/sys/net/ipv4/tcp_ecn</programlisting>
<para>You must arrange for that command to be executed at system boot.
Most distributions have a method for doing that -- on RedHat, you make an
@ -85,8 +94,29 @@
<title>Your external interface is eth0 and you want to disable ECN for
tcp connections to 192.0.2.0/24:</title>
<para><table><title>/etc/shorewall/ecn</title><tgroup cols="2"><thead><row><entry
align="center">INTERFACE</entry><entry align="center">HOST(S)</entry></row></thead><tbody><row><entry>eth0</entry><entry>192.0.2.0/24</entry></row></tbody></tgroup></table></para>
<para><table>
<title>/etc/shorewall/ecn</title>
<tgroup cols="2">
<thead>
<row>
<entry align="center">INTERFACE</entry>
<entry align="center">HOST(S)</entry>
</row>
</thead>
<tbody>
<row>
<entry>eth0</entry>
<entry>192.0.2.0/24</entry>
</row>
</tbody>
</tgroup>
</table></para>
</example>
</section>
<lot></lot>
</article>