Until now it was not possible to set up a VPN between two remote stations using private IPv4 addresses to access the Internet (e. g. 3G/4G networking).
This restriction no longer exists with IPv6, because every IPv6 device receives a public IPv6 address. Thus IPv6 can be used to set up an IPv4 VPN tunnel to interconnect two remote IPv4 networks, regardless of the IPv4 WAN addresses used at each site.
In the example shown, two local IPv4 networks are connected via an IPv4 VPN tunnel, which is established over an IPv6 Internet connection. The IPv4 VPN packets are given IPv6 headers and sent to the remote site via the IPv6 Internet connection (either native or via tunnel broker).
