What is a DNSBL?
Domain Name System Blacklists, also known as DNSBL’s or DNS Blacklists, are spam blocking lists that allow a website administrator to block messages from specific systems that have a history of sending spam. As their name implies, the lists are based on the Internet’s Domain Name System, which converts complicated, numerical IP address such as 18.104.22.168 into domain names like example.net, making the lists much easier to read, use, and search. If the maintainer of a DNS Blacklist has in the past received spam of any kind from a specific domain name, that server would be “blacklisted” and all messages sent from it would be either flagged or rejected from all sites that use that specific list.
About the SuperTool!
All of your MX record, DNS, blacklist and SMTP diagnostics in one integrated tool. Input a domain name or IP Address or Host Name. Links in the results will guide you to other relevant tools and information. And you’ll have a chronological history of your results.
If you already know exactly what you want, you can force a particular test or lookup. Try some of these examples:
(e.g. “blacklist: 127.0.0.2” will do a blacklist lookup)
Spamhaus tracks the Internet's worst Spammers, known Spam Gangs and Spam Support Services, and works with ISPs and Law Enforcement Agencies to identify and remove persistent spammers from the Internet."