SEC-01 / SECURITY
Blacklist Checker
Check whether a domain or IP is listed on major real-time blackhole lists (RBLs).
About the Blacklist Checker
If your domain or mail server IP lands on a DNS blocklist (RBL), your email starts bouncing or landing in spam across many providers at once. This tool checks your target against several major real-time blocklists so you can catch listings early.
What this tool checks
It resolves your domain or IP to an address and queries it against major RBLs including Spamhaus, SpamCop, Barracuda, and SORBS, reporting whether each one lists you.
If you're listed
A listing means that blocklist has flagged your IP for spam or abuse. Each RBL has its own delisting process. Fix the underlying cause first — compromised accounts, misconfiguration, or an open relay — then request removal.
Frequently asked questions
What is a DNS blacklist (RBL)?
A DNS-based blocklist is a published list of IPs known for sending spam or abuse. Mail servers query these lists to decide whether to accept, flag, or reject incoming mail from an IP.
How do I get removed from a blacklist?
First fix the cause — secure compromised accounts, close open relays, correct misconfigurations. Then use the specific blocklist's delisting form. Removal is often quick once the problem is resolved.
Why is my IP on a blacklist?
Common reasons include a compromised account sending spam, a misconfigured or open mail relay, shared hosting where another user was flagged, or a sudden spike in outbound volume that looks abusive.