This is se second part for this thread
Let's Encrypt fail over IPv6
Simplifying the subject
# ping6 google.com
connect: Network is unreachable
but
# ip address
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd...