--- a/net.rst	Fri Jul 21 17:52:02 2017 +0300
+++ b/net.rst	Fri Jul 21 17:54:10 2017 +0300
@@ -102,64 +102,6 @@
   $ sudo netstat -tulpn
   $ sudo lsof -i
 
-How disable IPv6?
-=================
-
-Debian kernel 2.6/Ubuntu ("official" method)/Fedora Core.
----------------------------------------------------------
-
-Comment in /etc/modprobe.d/aliases "alias net-pf-10 ipv6" and add alias
-"net-pf-10 off", "alias ipv6 off"::
-
-  $ sudo emacs /etc/modprobe.d/aliases
-  ...
-  $ cat /etc/modprobe.d/aliases
-  ...
-  # alias net-pf-10 ipv6
-  alias net-pf-10 off
-  alias ipv6 off
-  ...
-
-Reboot or::
-
-  $ sudo update-modules
-
-Another way is adding to /etc/modprobe.d/blacklist.local lines::
-
-  blacklist ipv6
-
-You can safely wipe out any IPv6 reference in ``/etc/hosts`` and
-``/etc/network/interfaces``.
-
-  http://wiki.debian.org/DebianIPv6
-                DebianIPv6
-
-RHEL4/Centos4.
---------------
-
-As for Debian, but ``/etc/modprobe.d/aliases`` has name ``/etc/modprobe.conf``.
-
-KDE.
-----
-::
-
-  $ cat /etc/environment
-  ...
-  KDE_NO_IPV6=true
-  ...
-
-Firefox.
---------
-
-See ``about:config`` page, set ``network.dns.disableIPv6`` to ``true``.
-
-Clear saved Windows networking passwords.
-=========================================
-::
-
-  cmd> rundll32.exe keymgr.dll, KRShowKeyMgr
-  cmd> control userpasswords2                 # another way
-
 Proxy auto-config.
 ==================