Most data on this website simply measures the number of IPv4 (A) and IPv6 (AAAA) records in the DNS. This does not neccesarily mean typical web services are actually available. To check this, each host is tested for a successful response on any three protocols: HTTP, HTTPS, SMTPS depending on the DNS record entry types (WWW or MX). HTTP - Websites (WWW hosts) HTTPS - Secure websites (WWW hosts) SMPTS - Secure email (MX hosts) The data shows a comparison between services successfully reachable over these protocols via IPv4 and IPv6.