Blacklist check
Blacklist (DNSBL) check
We check an IPv4 address against 9 popular spam lists to help you find out why mail ends up in spam.
For a domain, up to two of its IPv4 addresses (A records) are checked. IPv6 addresses are not checked (an address like ::ffff:1.2.3.4 is checked as IPv4). A list that did not answer or refused the query does not mean "listed", only "could not check": lists often block public DNS resolvers, try again later.