DNS Blacklist Checker

Check if your IP or domain is listed on major spam blacklists (RBLs)

Quick Examples

What are DNS Blacklists?

A DNS Blacklist (DNSBL) or Real-time Blackhole List (RBL) is a database of IP addresses and domains known for sending spam, hosting malware, or other malicious activity. Email servers check these lists before accepting messages. When you send an email, the receiving server looks up your IP in multiple blacklists. If you're listed, your email might be rejected, delayed, or marked as spam. It's an automated defense against millions of spam messages sent daily.

Consequences of Being Listed

Getting blacklisted can seriously impact your operations:

Critical Email Delivery Failure Your emails bounce or never arrive. Many servers outright reject mail from listed IPs.
High Spam Folder Delivery Emails get delivered but go straight to spam folders, drastically reducing open rates.
Medium Reputation Damage Being listed signals poor practices. Even after delisting, some damage to sender reputation remains.

How to Fix a Blacklist

Getting delisted requires fixing the root cause first, then requesting removal:

1. Identify the Problem

  • Check which blacklists have listed you
  • Read the listing reason in TXT records
  • Review server logs for spam activity

2. Fix the Root Cause

  • Remove malware and close security holes
  • Disable open relay and fix mail server config
  • Change passwords for compromised accounts

3. Request Delisting

  • Visit the blacklist's website (check results for URL)
  • Submit your IP for removal
  • Explain what you fixed (if required)

4. Prevent Future Listings

  • Monitor sending patterns and bounce rates
  • Use email authentication (SPF, DKIM, DMARC)
  • Maintain good list hygiene

Major Blacklists Explained

Spamhaus ZEN Combined IP list

Combines SBL, XBL, and PBL. The most widely used blacklist by volume.

Usage: Used by major email providers worldwide
Auto-removal: Usually after 24 hours clean
Website:
Check listing status
Spamhaus DBL Domain blacklist

Lists malicious domains used in spam, phishing, and malware.

Usage: Checks domain names in message content and headers
Auto-removal: Requires manual review
Website:
Check listing status
Spamhaus PBL Policy block list

Dynamic/residential IPs that should not send direct mail.

Usage: ISP-submitted. You shouldn't be sending from these IPs anyway.
Auto-removal: Requires proper mail setup via ISP's mail server
Website:
Check listing status
SpamCop User-reported spam

Based on spam reports from real users and spam traps.

Usage: Automated listing from spam reports
Auto-removal: 24 hours after last report
Website:
Check listing status
SORBS Multiple categories

Various lists for spam sources, dynamic IPs, open proxies, etc.

Usage: Different zones for different types of threats
Auto-removal: Varies by list, some require payment
Website:
Check listing status
UCEPROTECT Tiered system

Level 1 (single IPs), Level 2 (ISP ranges), Level 3 (countries/ASNs).

Usage: Aggressive listing, Level 2/3 can block innocent users
Auto-removal: Automatic after 7 days clean
Website:
Check listing status
Barracuda Commercial reputation

IP reputation system with multiple categories.

Usage: Common in enterprise email security appliances
Auto-removal: Automatic based on behavior improvement
Website:
Check listing status
PSBL IP blocklist

Passive Spam Block List - catches IPs sending to spam traps.

Usage: Popular with smaller mail servers and ISPs
Auto-removal: Automatic after 2-4 weeks of inactivity
Website:
Check listing status
DroneBL IP blocklist

Tracks compromised machines, botnets, and proxy abuse.

Usage: Originally for IRC, now used for email and web security
Auto-removal: Varies by listing type, typically 1-7 days
Website:
Check listing status