[system-administrators-guide] Adding note to "The sysconfig Directory" section: How to disable IPv6

[stephenw]

commit bb305a52251cd175578d00edf7234e8f9439b6b4
Author: Stephen Wadeley <swadeley at redhat.com>
Date:   Mon Mar 11 17:27:52 2013 +0100

    Adding note to "The sysconfig Directory" section: How to disable IPv6

 en-US/The_sysconfig_Directory.xml |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/en-US/The_sysconfig_Directory.xml b/en-US/The_sysconfig_Directory.xml
index becd1eb..298f46b 100644
--- a/en-US/The_sysconfig_Directory.xml
+++ b/en-US/The_sysconfig_Directory.xml
@@ -1410,6 +1410,13 @@
           </listitem>
         </varlistentry>
       </variablelist>
+       <note>
+      <para>If you want to completely disable IPv6, you should add these lines to /etc/sysctl.conf:
+<screen>net.ipv6.conf.all.disable_ipv6=1</screen>
+<screen>net.ipv6.conf.default.disable_ipv6=1</screen>
+</para>
+<para>In addition, adding <command>ipv6.disable=1</command> to the kernel command line will disable the kernel module <application>net-pf-10</application> which implements IPv6.</para>
+      </note>
       <warning>
         <title>Avoid using custom init scripts</title>
         <para>