Thanks for the reply.
That’s interesting, because it doesn’t match what I’m actually seeing.
IPv6 has been working reliably on my Connect Box 3 Fibre for several weeks now, despite previously being told by Sunrise support that IPv6 wasn’t available on this device.
Likewise, I have been successfully using the DMZ with my own ASUS router while IPv6 is enabled, so in my case DMZ certainly does work.
I think the real question is therefore what configuration Sunrise has actually applied to my connection, because it doesn’t appear to match either what support previously told me or what you’ve described here.
It would be helpful if someone from Sunrise could clarify exactly which operating modes and IPv4/IPv6 configurations are currently supported on the Connect Box 3 Fibre. It was this lack of clarity that I was trying to resolve because the posts here are apparently not consistent with what I see or what support told me. They’re not consistent with my expectations either but that ship has long sailed 😀