DNSBL (DNS Blacklist)
Public lists of domains and IPs associated with spam, queried by mail filters in real time. Spamhaus, SURBL, and URIBL are major ones.
Free · no signup · last reviewed August 29, 2026
The definition
Public lists of domains and IPs associated with spam, queried by mail filters in real time. Spamhaus, SURBL, and URIBL are major ones.
Why it matters to an owner
Getting listed quietly ruins deliverability. Check your sending domains monthly — it takes seconds.
This is the work. Want it done?
Everything here is free to use yourself — that’s the point. If you’d rather a senior marketer just handle it, in your accounts and your name: 20-minute call, no pitch deck.