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Is your mail server on a blocklist?

Enter an IP address, or a domain to check it and its mail servers. We query the blocklists that allow public lookups, tell you plainly where you're listed or clean, and link you straight to the lists that don't.

01 How blocklists work

Listed before anyone reads a word.

Receiving servers ask blocklists about the connecting IP, and about domains in the message, often before accepting it. A listing can mean rejection outright.

IP blocklists

SpamCop, UCEPROTECT Level 1, PSBL, Mailspike and DroneBL, checked live, list sending IPs seen spamming, hitting spam traps or running compromised software. Spamhaus ZEN and Barracuda are a click away.

Domain blocklists

Spamhaus DBL, SURBL and URIBL list domains that appear in spam or phishing. Their terms don't allow lookups from a public tool like this one, so we link to each list's own checker.

Honest “couldn't check”

Lists sometimes refuse a query or don't answer in time. When a list doesn't give a real answer, we say so, rather than calling you clean.

02 Questions

Common questions.

Something else? Write to us — a real person answers, usually the same day.

Talk to us
What does it mean if I'm listed?+
That the list has seen spam, spam-trap hits or abuse from that IP or domain. Receivers that use the list may reject or junk your mail. Find and fix the cause first (a compromised account, a bad mailing list, a hacked form), then use the list's removal page.
Why don't you check Spamhaus, SURBL and URIBL here?+
Their free lookups are for low-volume, non-commercial use, and a public tool on a company's website doesn't qualify. Barracuda only answers mail servers registered with it. Rather than bend those terms, we link straight to each list's official checker, with your IP or domain filled in where the list supports it. Its answer is the authoritative one.
Why does a list say “couldn't check”?+
Lists sometimes refuse a query or don't answer in time, and some reply with an error code instead of a result. That isn't a listing. We report it separately so a refusal is never mistaken for a clean result.
I use Google Workspace or Microsoft 365. Do I need this?+
Less so: you send from their IPs, which they manage. Checking your domain is still worthwhile, since domain blocklists judge the domain itself, wherever the mail comes from.
Which lists matter most?+
Spamhaus is consulted by a large share of receivers, so check it first with the link in your results: a Spamhaus listing is the most urgent. SpamCop and the domain lists matter too. Smaller lists rarely block mail on their own but are worth clearing.

03 More free tools

Keep checking.

Each tool answers one question about a domain's email. All free, no signup.

All free tools ▶
Reputation→

Email health score

Authentication, blocklists, routing and domain age combined into one A–F grade.

DNS & domains→

Domain age checker

Registration date, expiry and registrar from official RDAP data, and what age means for mail.

Authentication→

Email deliverability checker

SPF, DKIM, DMARC, MX and MTA-STS in one pass, with a score and the fix for anything that fails.

Mail servers we watch, so you don't.

Every domain you run in one inbox, from $3 a mailbox. 14 days free, no card.

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