Followed the exact steps as described in https://help.directadmin.com/item.php?id=353 on two Centos 7 machines (one VM and other dedicated). But tests show that webserver and nameservers are unable to connect. Still, ifconfig -a shows the correct IPv6 adresses. Also disabled CSF for testing purposes but makes no different. I can however see IPv6 ports scans comming in and blocked by CSF when enabled.

What am I missing here?