Networking
IPv4 and IPv6
Public IPv4 on every VPS. IPv6 where the location provides it.
Addresses
The portal lists IPv4 and, when allocated, IPv6. Point A records at IPv4 and AAAA at IPv6. Do not publish AAAA if the web server is not listening on IPv6.
rDNS
Reverse DNS is useful for mail. Set it on the server IPs tab when the capability is enabled. Mail hosts often require rDNS to match the HELO name.