What is an email blacklist?
Spam blocklists, or DNSBLs, are lists of IP addresses that have sent spam or show signs of abuse, such as an infected computer or an open relay. Mail servers look up the sending IP before accepting a message; if it is listed, the email may be rejected or sent to spam — even if it is a genuine message from you.
How to use the checker
- Enter your mail server’s IP address, or your domain — its website and first mail server are found and checked for you.
- Read the results: each list shows Listed, Not listed, or No answer.
- If you are listed, fix the cause first, then follow the list’s removal link.
If you are listed
- Find the cause: a hacked website or email account sending spam, a compromised computer on your network, or a contact form abused by bots.
- On shared hosting the IP is shared with other customers — ask your host to move you or to fix the listing.
- Most lists remove an address automatically after the spam stops; others have a request form. Repeated listings take longer to clear.
About the lists checked
This tool queries 13 well-known blocklists through public DNS resolvers. Spamhaus and a few others refuse queries from public resolvers, so they are not included here — check those directly at check.spamhaus.org. Large providers such as Gmail and Microsoft also keep private reputation data that no public tool can show.
Frequently asked questions
Why is my IP blacklisted when I did not send spam?
Another customer on the same shared server, a hacked account or website, or malware on a device in your office can send spam from your IP without you knowing.
How long does it take to get removed?
From a few hours to a few days once the problem is fixed. Some lists expire listings automatically; others need a removal request.
Does being listed on one blocklist matter?
It depends on the list. SpamCop and Barracuda are widely used, so a listing there affects delivery; some smaller lists have little effect.