Email blocklist · DNSBL · /24 subnets
TUE · 28 JUL 2026
UCEPROTECT Level 2
About
UCEPROTECT escalation level 2. Listing extends to the whole /24 once enough IPs within are L1-listed. Aggressive and prone to collateral damage; use with caution.
Listing criteria
Listing applied to the entire /24 once a threshold of L1-listed IPs is reached within it. Aggressive; commonly causes collateral damage to innocent neighbours.
How to query
For an IP address 1.2.3.4, query reversed-octets-dot-zone:
dig +short 4.3.2.1.dnsbl-2.uceprotect.netA 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.