My home network has successfully used both IPv4 and IPv6 since around 2013.
The IPv4 WAN is a static Plusnet address.
The IPv6 WAN is a 6in4 tunnelled connection using the Hurricane Electric IPv6 Tunnel Broker.
On the following screenshots of my router's WAN traffic, the upper graphs show the IPv4 WAN traffic, and the lower graph shows the IPv6 traffic. The blue traffic shows the incoming data from the internet in to my router, whereas the orange traffic is the outgoing data being sent from my router towards the internet. Because the IPv6 traffic is tunnelled over IPv4, whenever IPv6 is present on the lower graph, then there will be the same corresponding traffic shown on the upper IPv4 graph.
Doing a typical IPv4 speed test, in this case using Ookla speedtest.net
I get the expected 68Mbps download and 18Mbps upload showing on the upper IPv4 WAN graph
and barely any IPv6 traffic detected.
This time, doing an IPv6 speed test, in this case using speedtest.tools.uebi.net
I get the expected 68Mbps download and 18Mbps upload showing on the lower IPv6 WAN graph
and the corresponding tunnelled traffic showing on the upper IPv4 graph.
So far all is as expected ! - and with most other speed test checkers I get the same results.
HOWEVER when I use the ThinkBroadband Broadband Speed Test something different occurs !
If I select the [Run IPv4] option, something odd happens.
The download portion of the speedtest occurs correctly using the chosen IPv4 protocol,
however the upload is being sent from my network using IPv6 ! ?.
The opposite effect occurs if I select the IPv6 enabled [Run Test] option
This time the download portion of the speedtest occurs correctly using the chosen IPv6 protocol,
but now the upload is being sent from my network using IPv4 ! ?.
Can anyone else with IPv6 repeat this odd behaviour using the ThinkBroadband speed test ?