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Free tool

Email Blacklist Checker

Enter a domain or IP to check it against the major spam blocklists — instantly, for free.

Checks 4 IP blocklists + 2 domain blocklists via public DNS. Free, no sign-up.
Short answer: A blacklist (DNSBL) listing means a mailbox provider or spam filter has flagged your sending IP or domain as a spam source. Even one blocklist hit can tank your deliverability — this tool checks the major ones in seconds.

What we check

If you're listed

  1. Identify and fix the root cause — spam complaints, a compromised sender, or a bad list.
  2. Visit the specific blocklist's delisting page and submit a removal request.
  3. Keep sending clean going forward — most blocklists watch for repeat offenses.

A blacklist hit is a reputation problem — the same category of issue that warmup fixes for cold or damaged domains. See why emails go to spam for how reputation, content, and authentication fit together.

MailPilot

Clean list, still landing in spam?

Blacklist and content aren't the whole story — sender reputation matters too. MailPilot warms up your mailbox to build the trust that keeps you off blocklists in the first place.

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Blacklist checker — FAQ

How does a blacklist checker work?

It looks up a specially-formatted hostname on each blocklist's DNS server — for IP blocklists, the reversed IP plus the blocklist's domain (e.g. 4.3.2.1.zen.spamhaus.org); for domain blocklists, your domain plus theirs. If that lookup resolves to an IP address, you're listed. If it returns nothing (NXDOMAIN), you're clean. This tool runs those lookups from your browser via public DNS.

What do I do if I'm on a blacklist?

First, fix whatever caused the listing — usually high spam complaints, sending to a bad list, a compromised server, or being on a dynamic/residential IP range not meant for sending mail. Then visit that specific blocklist's delisting page (each one is different — Spamhaus, SpamCop, and Barracuda all have their own removal request forms) and follow their process. Delisting is not automatic even after you fix the cause.

Why is my IP blacklisted but not my domain?

IP and domain reputation are tracked separately. A shared IP (common on cheap hosting or ESPs) can get blacklisted because of another customer's bad behavior, even if your domain and content are clean. If you're on shared infrastructure, ask your provider about their abuse policy or consider a dedicated IP once you have volume to justify warming it up.

How long does it take to get delisted?

It varies by blocklist — some auto-expire listings after the sending pattern that caused it stops (hours to days), while others (like Spamhaus SBL) require a manual delisting request and review, which can take anywhere from a few hours to a few days depending on the blocklist and the severity of the listing.