How to Use PSBL
PSBL (Passive Spam BlockList) helps protect your mail server by identifying known spam sources. Here's how to integrate and use our service effectively.
Purpose
PSBL focuses on listing the most severe spam offenders. We recommend using it for outright blocking rather than incorporating it into a scoring system. Unlike scoring-based filters that evaluate spam probability, PSBL provides definitive blocking decisions for confirmed spam sources, saving your server resources while maximizing protection.
DNS Zone Configuration
Query the PSBL blacklist through our DNS zone: psbl.sorbl.com
Configure your email server or filtering system to query this DNS zone during the email filtering process. Below are examples for common MTAs:
Postfix (main.cf):
Manual DNS Query:
dig 8.8.8.8.psbl.sorbl.com
Query Formats
To check if an IP address is listed, perform a DNS lookup for:
Example: For IP 192.0.2.10, reverse the octets to 10.2.0.192 and query:
A successful lookup (returns an A record) means the IP is listed. A timeout or NXDOMAIN means the IP is clean.
Disclaimer
While we strive to maintain accuracy and minimize false positives, no blacklist is perfect. PSBL is provided as a free service without warranty. By using this service, you assume all associated risks. If you do not agree with these terms, please do not use PSBL.
PSBL Statistics
📋 Total Unique IP Addresses Blocked: 21,170
📊 Total Spam Attempts Processed: 36,922