Email blacklist checker

A DNS blacklist (DNSBL) is a list of IP addresses that have sent spam, published so mail servers can look up a sender as email arrives. Being listed means some receivers will junk or refuse email from that address.

Why we check fewer lists than some sites

Each list sets its own terms, and many don't allow lookups on behalf of the public or for commercial use without a paid licence. Spamhaus, the best known, is free only for small non-commercial use, so we never query its public mirrors. We read each list's terms and include only those that allow this use. Today that's PSBL, whose operator says "Anybody is free to use PSBL". We'll add others as their operators confirm.

What the answers mean

• Listed: the list returned a 127.0.0.x code for the address. Follow the list's removal process once the cause is fixed; see how to get off a blacklist.
• Not listed: the list has no entry for the address.
• No answer: the list didn't reply or refused the query. That says nothing about the address, so we never count it as a listing.

For a domain, we check the addresses of its mail servers (its MX records). The servers that send its email may be different, such as Microsoft 365 or a newsletter service; the free email test checks the address a real message came from.

In the app, Domain Health Hub checks every client domain's mail servers and the sending servers seen in its DMARC reports against more lists every day, and alerts you when one is listed.