Blacklist Check
Check if an IP address appears on spam or abuse blacklists.
Queries the IP against a curated set of public DNSBLs (DNS-based blocklists) used by mail
servers and abuse-detection systems — Spamhaus, Barracuda, SORBS, and similar. A listing means
at least one of these projects has observed spam, brute-force, or other abusive behavior from
this IP recently. A clean result means the IP is not currently flagged by the lists we check;
it doesn't guarantee the IP has a perfect reputation everywhere.
Running...
What "listed" means
- Each row is one blocklist's verdict for this IP. "Listed" = present in that list. "Not listed" = absent.
- Different lists have different criteria. Spamhaus is the most widely respected; some smaller lists are noisy or slow to remove cleared IPs.
- A few listings on minor lists usually does not block your email delivery. Being on Spamhaus SBL/XBL/PBL does, immediately, for major mail providers.
Common use cases
- Email deliverability debugging — your mail server's IP being on Spamhaus is one of the top reasons messages get rejected or land in spam.
- Reputation check for outbound IPs — before assigning a cloud IP to a new mail / API service, confirm the previous tenant didn't burn it.
- Investigating an inbound IP — known-bad sources in your access logs warrant a closer look.
- VPN exit nodes — many residential ISPs' blocks end up listed when shared by VPN users; this is why some sites silently block VPN traffic.
If your IP is listed
- Each blocklist has a removal process. Spamhaus, Barracuda, SORBS each provide a request-removal page. Most ask you to fix the underlying issue first (compromised account, open relay, weak forwarding rules).
- Removal typically takes hours to days. Cloud providers sometimes won't reassign the IP to you for a cooldown period after it's cleared.
- If you operate a mail server, set up SPF, DKIM, DMARC properly and monitor the abuse mailbox; that prevents re-listing.