Is your IP on a
blocklist?

Blocklists list IP addresses, not domains — so when you enter a domain, this tool first resolves it to the IPs that actually matter: your website's A record and the IPs behind your MX (mail) records. A spam-trap listing on your mail IP is what filters act on; a listing on a shared web host you don't send from usually isn't your problem. Checking both, labelled by role, tells you which is which.

The big two — Spamhaus and SpamRats — refuse queries from public DNS resolvers (they sell direct-feed access to high-volume users). A refused query is technically indistinguishable from 'not listed', so showing a green 'clean' would be a lie. Instead we link you straight to their official lookup pages. Every other list here was tested live against the universal 127.0.0.2 test entry before shipping.

Two of the oldest reputation signals in email. A missing reverse DNS (PTR) record on a sending IP is itself a reason receivers distrust you — legitimate mail servers have one. The ASN (from Team Cymru's public IP-to-ASN database) shows which network owns the IP; being on a residential or 'bulletproof' ASN is a red flag regardless of any blocklist.

Each listing links to that list's delisting page. First, fix the cause — an open relay, a compromised account, a bad list that generated complaints — because re-listing is instant if you don't. Single-IP lists (PSBL, UCEPROTECT L1) often auto-expire within days of clean behaviour; others need a manual request. UCEPROTECT L2/L3 list whole networks, so the fix is usually your host's job, not yours.

Reactively when deliverability drops, and proactively on a schedule if you send volume — reputation can change overnight from one compromised mailbox. A one-off check like this is a snapshot; continuous monitoring across every sending IP is what catches a problem the morning it starts, which is the job Norbelys does on your connected mailboxes.