Check your mail server’s IP address or sending domain against 14 active, documented blocklists — and get the exact listing reason plus each provider’s free removal page.
Enter your mail server’s public IP or your sending domain. We query each blocklist’s live DNS zone and report exactly what it answers.
Results appear here: one row per blocklist, with the exact listing code, what it means, and the provider’s removal page when you are listed.
Privacy: we send only the IP address or domain you enter to public DNS blocklist zones over the DNS protocol. Lookups are not logged with your identity and results are never stored.
Paste your mail server’s public IPv4/IPv6 address or your sending domain. Domains are resolved to their IPs so both list types are covered.
Your target is looked up in 14 active blocklist zones using standard DNS queries — the same mechanism receiving mail servers use.
A 127.0.0.x answer means listed, and the code tells you which dataset flagged you. No answer means not listed. Timeouts and refusals are shown as unknown — never as clean.
A DNS-based blocklist is a public database, queried through DNS, that lists IP addresses or domains observed sending spam or abuse. Receiving mail servers check these lists while a message is arriving and may reject or junk mail from listed senders.
For an IP address we reverse it (octets for IPv4, nibbles for IPv6) and query each provider’s DNS zone. For a domain we check the domain-based lists directly and also resolve the domain to its IP addresses so the IP lists are covered. An answer in the 127.0.0.0/8 range means "listed" and the code explains why; no answer means not listed; a timeout or refusal is reported as unknown — never as clean.
First find and fix the cause: spam complaints, a compromised account or an open relay. Then use the provider’s removal link shown in the results. Delisting from reputable lists is always free — never pay a third party promising removal. Some lists, like SpamCop, remove you automatically once the reports stop.
Some operators (Spamhaus, for example) refuse queries that arrive through public or shared resolvers, and busy zones can time out. We report those checks as unknown rather than pretending they came back clean, so an "all clear" here is only as strong as the checks that actually completed.
Not necessarily. Public blocklists are only one signal. Gmail, Outlook and Yahoo keep private reputation data, and engagement, authentication (SPF, DKIM, DMARC) and content all matter. A clean result here means no public list we checked flags you — nothing more.
We query 14 active, documented zones — 10 IP lists (including Spamhaus ZEN, Barracuda, SpamCop and Mailspike) and 4 domain lists (including Spamhaus DBL, SURBL and URIBL). We deliberately removed dead zones like SORBS, WPBL and NixSPAM, and lists that now require paid keys, so every result you see is real.
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