Email Blacklist Checker
Check a mail server's IP against multiple block lists — with the individual result from each source shown separately.
About this tool — one listing is not a verdict
This checks a mail server's IP against each block list individually and shows every result separately, deliberately. A single listing on one source is a signal worth investigating, not proof an IP is universally malicious — block lists vary widely in accuracy, update frequency, and what behavior triggers a listing, and shared hosting or dynamic residential ranges can carry a previous occupant's listing for a period after reassignment.
Why this matters for email specifically
Many receiving mail servers check the sending server's IP against one or more of these lists before accepting a message — a listing can mean legitimate mail silently lands in spam folders or gets rejected outright, often with no notification to the sender.
If your mail server is listed
Each list operator publishes its own delisting process, typically a self-service form once the underlying cause (an open relay, a compromised account, a spam campaign) has actually been resolved — delisting without fixing the cause usually results in being relisted quickly.
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