Email blocklist · DNSBL · IP addresses
TUE · 28 JUL 2026
Spamhaus PBL
About
Policy Block List. Lists IP ranges that ISPs have declared should not send mail directly. Maintained from registry data.
Listing criteria
IP ranges that, according to the ISP that operates them, should not be sending mail directly. Listing comes from the ISP itself, not from observed abuse; the list expresses operator policy.
How to query
For an IP address 1.2.3.4, query reversed-octets-dot-zone:
dig +short 4.3.2.1.pbl.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.