Free Blacklist Checker
FreeFree blacklist checker — instantly check security configuration for any domain or email. Protect your domain reputation. No signup required.
How Do Email Blacklists Work?
Email blacklists (or blocklists) are real-time databases maintained by independent organizations (like Spamhaus, SORBS, or Barracuda) that list IP addresses and domains known to send spam. When you send an email, the receiving mail server checks these blocklists. If your IP or domain is listed, the server will either reject the email or route it directly to the spam folder.
Why Did My Domain Get Blacklisted?
- High Spam Complaints: Too many recipients clicked the "Mark as Spam" button on your emails.
- Spam Traps: You emailed a "spam trap"—a hidden email address specifically designed to catch senders who scrape addresses or buy lists.
- Compromised Server: Your mail server or website was hacked and is being used by a third party to send outbound spam.
- Shared IP Address: If you use a shared IP (common with cheap hosting or marketing platforms), you might be penalized for the bad behavior of another sender on the same IP.
How to Get Removed from a Blacklist
If you find your domain or IP on a blocklist, do not panic. First, identify and fix the root cause (e.g., stop emailing purchased lists, secure your server, or clean your list). Then, visit the specific blocklist's website and follow their delisting process. Most blocklists offer a self-service removal form for first-time offenders.
Frequently Asked Questions
What is an email blacklist and how does it affect deliverability?
Email blacklists (also called DNSBLs — DNS-based Blocklists) are real-time databases of IP addresses and domains known for sending spam. When a receiving mail server accepts an incoming message, it checks the sender's IP against major blacklists. If listed, the email is typically rejected or marked as spam before reaching the inbox. Being listed on major blacklists like Spamhaus, SORBS, or Barracuda can severely impact deliverability across all email providers.
How do I get removed from an email blacklist?
To delist from an email blacklist: (1) Identify which list you are on using our Blacklist Checker. (2) Fix the underlying issue — spam complaints, open relay, compromised server, or sending to invalid addresses. (3) Visit the blacklist's website and submit a delist request (most have a form). (4) Spamhaus and URIBL offer self-service removal for valid requests. (5) Monitor your IP reputation weekly to catch new listings quickly.
Is the Blacklist Checker tool free to use?
Yes. The Blacklist Checker is completely free on FreeMailTools.com with no registration required. We offer 200+ free email security, validation, DNS, and deliverability tools for developers, sysadmins, and security researchers.