Internal blocklist operated by the TRIUMF particle physics laboratory in Vancouver. No longer actively maintained or publicly deployed.

The highest-severity tier of GBUdb's IP reputation system. Lists IPs with so poor a reputation that no legitimate mail has been observed from them. Used by ...

Small independent Swiss SMTP blacklist. Discontinued. DNS queries no longer return valid responses. Historical reference only.

Dutch DNSBL that was part of the FabelSources anti-spam project. Discontinued. No longer operational.

A DNSBL zone associated with Kemp Technologies and Spamhaus network infrastructure. No longer actively maintained. DNS responses are unreliable.

Independent DNSBL with both RBL (IP-based) and standard spam lists. Populated from trap networks and community reports. Used in some SpamAssassin ...

German DNSBL focused on anonymous mail relay abuse and spam sources. Used in German mail infrastructure.

Blocklist that focused on malware-sending and compromised host sources. Discontinued. No longer operational.

Small independent DNSBL. Discontinued. Historical reference only.

JumpStart Internet Packet Pro Guard — independent spam blocklist from the early 2000s. Long discontinued. Historical reference only.