DNS Reputation Blacklists (RBLs)

We offer our IP address blacklists as open-access DNS RBLs.

If you intend to do more than 10000 queries per day, please contact us beforehand. Failure to do so may result in filtering.

Our DNS RBL Zones

How it works

Our DNS blacklists are structured in the same way most others are. DNS is structured from the right to left rather than left ot right, to accomodate this, you would take an IP address such as and reverse the octets, You would then add on the DNS zone onto that transformed IP, e.g. then perform an "A" query.

dig IN A

if you receive no result (or NXDOMAIN), this is good, it means the IP address is not listed. However, if you receive a response of "" this means the host in question is listed, what you do with that return value in your decision is up to you.

Of course our DNS RBLs are designed for automated lookup tools, so most tools that can take DNS RBLs are already designed with this in mind.