Hello Nikos,
> It seems that this was an MTU issue. Once the MTU is set over 1280
> bytes in the tun device the IPv6 address appears. I've now adjusted
> the way the suggested MTU value from openconnect (which seems fixed to
> 1280) is taken into account and a larger MTU is negotiated, thus
> allowing IPv6.
you probably already know that. But the minimum MTU for IPv6 is 1280.
And the MTU for IPv6 is end-to-end that means that the smallest link
between the two ends determines the MTU. With IPv4 it is layer 3 hop bu
layer 3 hop. The reaso for doing it end-to-end for IPv6 is probably
because it wasted a load of CPU power in the past on routers to fragemnt
and defragment the packets.
Cheers,
Thomas
