DKIM Studio
Blacklist checker
Enter a domain and we resolve its mail (MX / A) IPs and check each one against the major DNS blacklists — Spamhaus, Barracuda, SpamCop, SORBS and more — plus the domain itself against URI blacklists. A listing is one of the most common reasons legitimate mail lands in spam.
Why run this from a server
Several blacklists — Spamhaus in particular — refuse queries that come through big public resolvers like 8.8.8.8. We run the lookups from our own recursive resolver, so the answers are the ones your recipients' mail servers actually see, not a blocked or cached result.
If you're listed
Find and fix the cause first — a compromised account, an open relay, or a misconfigured server sending spam — then use each blacklist's own removal form to request delisting. Getting your DKIM, SPF and DMARC in order and publishing MTA-STS all help keep you off them.