Since 2.3.0, OpenVPN officially supports IPv6, and all widely used
 patches floating around for older versions have been integrated.
 

 IPv6 payload support
 --------------------

 This is for "IPv6 inside OpenVPN", with server-pushed IPv6 configuration
 on the client, and support for IPv6 configuration on the tun/tap interface
 from within the openvpn config.
 
 The code in 2.3.0 supersedes the IPv6 payload patches from Gert Doering,
 formerly located at http://www.greenie.net/ipv6/openvpn.html
 

 The following options have been added to handle IPv6 configuration,
 analogous to their IPv4 counterparts (--server <-> --server-ipv6, etc.)

      - server-ipv6
      - ifconfig-ipv6
      - ifconfig-ipv6-pool
      - ifconfig-ipv6-push
      - route-ipv6
      - iroute-ipv6

 see "man openvpn" for details how they are used.

 
 
 
 IPv6 transport support
 ----------------------
 

 This is to enable OpenVPN peers or client/servers to talk to each other
 over an IPv6 network ("OpenVPN over IPv6").
 
 The code in 2.3.0 supersedes the IPv6 transport patches from JuanJo Ciarlante,
 formerly located at http://github.com/jjo/openvpn-ipv6
 

 OpenVPN 2.4.0 includes a big overhaul of the IPv6 transport patches
 originally implemented for the Android client (ics-openvpn)

 IPv4/IPv6 transport is automatically is selected when resolving addresses.
 Use a 6 or 4 suffix to force IPv6/IPv4:

 
   --proto udp6

   --proto tcp4

   --proto tcp6-client

   --proto tcp4-server

   --proto tcp6 --client / --proto tcp6 --server
 

 On systems that allow IPv4 connections on IPv6 sockets
 (all systems supporting IPV6_V6ONLY setsockopt), an OpenVPN server can

 handle IPv4 connections on the IPv6 socket as well, making it a true

 dual-stacked server. Use bind ipv6only to disable this behaviour.

 
 On other systems, as of 2.3.0, you need to run separate server instances
 for IPv4 and IPv6.