PSBL

What is PSBL?

PSBL (Passive Spam BlockList) is a real-time DNS blacklist that identifies and blocks IP addresses sending unsolicited spam emails. Our goal is to protect email servers worldwide from spam while minimizing false positives.

What IP Addresses Are Listed?

PSBL focuses on identifying and listing IP addresses that engage in spam activity, including:

• Compromised machines ("zombies") - Systems hijacked by malware to send spam
• Open proxies & relays - Servers allowing unauthorized email transmission
• Direct spam sources - Systems sending unsolicited bulk email

Major Email Providers Exempt from Auto-Listing

To prevent disruption of legitimate email services, the following major providers are exempt from automatic listing on PSBL:

Note: Google, Yahoo, and Microsoft (Outlook/Hotmail) are legitimate email providers with large, dynamic IP pools. While abusers may use these platforms to send spam, listing their frequently changing IP addresses is ineffective. PSBL focuses on static spam sources that consistently send unsolicited email. If you receive spam from a compromised account on these platforms, report the abuse directly to the provider rather than relying on IP-based blocking.

What PSBL Does NOT Do

• No active probing - PSBL never makes connections to other machines to "test" anything
• No SMTP relay testing - We don't test for open relays
• No IP ranges - PSBL lists individual IPs only. While some blacklists block entire /24 subnets, we focus on specific offenders to minimize false positives.
• No dynamic IP discrimination - We don't care if an IP is dynamic or static — spam is spam
• No personal identification - We never attempt to associate IP addresses with persons or organizations
• No external submissions - We don't accept revenge listings ("disgruntled ex-employee" or "competitor")

What PSBL Does Do

• Focuses on spam not already covered by other reputable lists (Spamhaus, SpamCop, Barracuda, DroneBL, etc.)
• Automates the listing and removal process for quick self-service
• Lists IP addresses that send unsolicited email regardless of type

PSBL Does NOT List Based On:

• Invalid or missing MX records
• Missing or incorrect reverse DNS (rDNS)
• Dynamic IP addresses (unless they send spam)

These issues are typically handled at the SMTP level by properly configured MTAs (Mail Transfer Agents).

For Email Marketers

Email marketing companies may allow users to purchase email lists or crawl for email addresses on web pages. However, if these activities result in spam reports, the associated IP addresses may be listed on PSBL.

To avoid being listed:

• Obtain explicit consent before sending marketing emails
• Provide clear and easy unsubscribe options
• Follow anti-spam laws (CAN-SPAM, GDPR, CASL, etc.)

Legal Disclaimer

Use entirely at your own risk. This list is based on information believed to be reliable, but no warranty is made that it is accurate or complete. PSBL is provided as a free service without guarantee. By using this service, you assume all associated risks.

Removal: PSBL operates in an entirely automated way — you can remove your listing yourself through our automated system.