Email blocklist · DNSBL · Newly-registered domains
TUE · 28 JUL 2026
Spamhaus ZRD
About
Zero-Reputation Domains list. Heuristic signal for newly-observed domains in messages, often a strong spam indicator.
Listing criteria
Listing for domains registered within the last 24 hours. Useful as a heuristic input rather than a hard block, since legitimate freshly-registered domains exist.
How to query
For an IP address 1.2.3.4, query reversed-octets-dot-zone:
dig +short 4.3.2.1.zrd.spamhaus.orgA returned IP (such as 127.0.0.2) means listed. Each blocklist has its own set of return codes meaning different things; the operator's documentation explains theirs.