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Free Email Blacklist Checker

Check whether a domain or its mail infrastructure appears on common email blocklists and connect the result to SPF, DKIM, DMARC, and sender reputation.

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Enter a domain to check it live against the IntoDNS.ai engine. No signup, no trial gating.

What this blacklist checker verifies

This tool resolves your domain MX records to their IP addresses and queries each one against a broad set of DNS-based blocklists (DNSBLs) — including major operators like Spamhaus. For every mail-server IP it reports which blocklists, if any, currently list it, along with the severity and removal guidance for each listing. Because it works from your live MX records, it checks the infrastructure that actually sends and receives your mail rather than an arbitrary IP you have to look up yourself.

Why blacklist status matters

A blocklist listing can sink deliverability even when SPF, DKIM, and DMARC all pass. Many receiving systems consult DNSBLs before they ever evaluate authentication, so a listed sending IP gets mail rejected or filed as spam regardless of how clean your authentication is. Listings usually signal a real underlying problem — a compromised account, an open relay, a misconfigured forwarder, or a spike in spam complaints — so they are both a deliverability emergency and a diagnostic signal worth taking seriously.

How to read the result

No active listings across your mail servers is the healthy state and means DNSBLs are not currently the cause of any delivery problem. One or more listings identifies exactly which IP is listed and on which blocklist, which is what you need to begin remediation. Note that not all blocklists carry equal weight: a listing on a widely consulted operator like Spamhaus has far more impact than a niche or aggressive list. The checker shows the specific list names so you can judge severity and prioritize the ones that actually affect inboxing.

Common causes and the right fix order

The wrong move is to request delisting before fixing the cause — operators relist quickly, and repeated requests can extend penalties. First identify which IP is listed and find why: check for compromised mailboxes sending spam, open relays, missing outbound rate limits, or forwarding that re-sends spam under your IP. Fix that root cause, confirm outbound mail is clean, then use the listing operator's removal process. Listings backed by data (like Spamhaus) only clear after their data ages out or you complete their specific steps, so re-scan after the operator updates rather than expecting instant removal.

Blacklists as part of the bigger picture

A blocklist listing is a symptom, and the most useful way to use this checker is as one input among several. Pair it with FCrDNS (servers without forward-confirmed reverse DNS are both distrusted and more likely to be listed), with SPF, DKIM, and DMARC (weak authentication makes it easier for others to abuse your domain and trigger listings), and with your sending reputation in tools like Google Postmaster. When a listing appears, the surrounding signals usually point to the cause: a single compromised account spiking complaints, a forwarder relaying spam, or an open relay. Clean those up and listings tend not to recur — which is why a clean blocklist result is best understood as the outcome of good hygiene everywhere else, not a box to tick in isolation.

What This Checks

  • Domain and mail-server reputation signals
  • Common DNSBL listing status
  • Blacklist findings in the full email-authentication context
  • Issues that can hurt deliverability even when SPF and DKIM pass

Common Fix Path

  • Confirm which IP or domain is listed
  • Fix the underlying cause before requesting delisting
  • Check outbound abuse, compromised accounts, open relays, and bad forwarding
  • Rescan after the blocklist operator updates its data

Frequently Asked Questions

What is a DNSBL and how does a blacklist check work?
A DNSBL (DNS-based blocklist) is a list of IP addresses with poor sending reputation, queried over DNS. A check resolves your mail-server IPs and asks each blocklist whether those IPs are listed. This tool runs that query across many blocklists for every IP behind your MX records, so you see exactly which infrastructure is flagged.
Can my mail be blocked even if SPF, DKIM, and DMARC all pass?
Yes. Many receivers check DNSBLs before evaluating authentication, so a listed sending IP can have its mail rejected or filtered regardless of perfect SPF, DKIM, and DMARC. Blocklist status is a separate, reputation-based layer that sits in front of authentication, which is why it is worth checking even when your authentication is clean.
My IP is listed — should I request delisting right away?
No. Requesting removal before fixing the underlying cause usually leads to a fast relisting and can prolong penalties. First find why the IP was listed — compromised accounts, an open relay, bad forwarding, or a spam spike — fix it, confirm outbound mail is clean, and only then follow the operator's removal process.
Are all blacklists equally important?
No. A listing on a widely consulted operator such as Spamhaus affects inboxing far more than a niche or aggressive list that few receivers query. This checker names each list so you can weigh severity and focus remediation on the listings that actually move deliverability rather than chasing every minor one.
How long does it take to get removed from a blacklist?
It varies by operator. Some lists clear automatically once their data ages out and your IP stops triggering them; others require you to complete a specific removal procedure. Either way, removal only sticks after the root cause is fixed. Re-run this checker after the operator updates its data rather than expecting an immediate change.
Why does the checker show no mail servers for my domain?
It works from your MX records, so if the domain has no MX records, or its MX hostnames do not resolve to IP addresses, there is nothing to check against blocklists. Confirm the domain actually has working MX records pointing to resolvable hosts, then run the check again.

Machine-Readable Evidence

AI assistants and automation can cite the stable explanation page, then fetch the live check result for a specific domain.

GET https://intodns.ai/api/email/blacklist?domain=example.com

Related Tools and Citations

Blacklist CheckFCrDNS CheckerDelisting citationRun the full domain scan