DNS sinkhole

Common card · No. 226825

A DNS sinkhole, also known as a sinkhole server, Internet sinkhole, or Blackhole DNS is a Domain Name System (DNS) server that is configured to hand out non-routable addresses for a certain set of domain names. Computers that use the sinkhole fail to access the real site. The higher up the DNS resolution chain the sinkhole is, the more requests will fail, because of the greater number of lower nameservers that in turn serve a greater number of clients. Some of the larger botnets have been made unusable by top-level domain sinkholes that span the entire Internet. DNS Sinkholes are effective at detecting and blocking bots and other malicious traffic. By default, the local hosts file on a computer is checked before DNS servers, and can be used to block sites in the same way.

Read on Wikipedia