All-in-one DNSBL checker written in Go using every publicly known DNSBL.
DNSBL is also known as RBL or DNS blacklist.
Features
Fast. All lists are checked simultaneously. It takes about 10 seconds.
Cross-platform. Works on Windows, macOS and Linux.
No dependencies. Everything you need to run dnsbl_checker is in a single file.
Nagios/Icing/Sensu compatible. dnsbl_checker exits with the appropriate exit code.
Complete. dnsbl_checker can check IPv4 addresses and domains. All against blacklists and whitelists.
Flexible. You can exclude one or more DNSBLs from the check, or only check against a select few.
Other
IPv6 is not supported because it's mostly useless in DNSBL context. Best solution is to not bind your SMTP server to an IPv6 address, so you cannot receive any email from IPv6 sources.