DNS sinkhole

From Wikipedia, the free encyclopedia
Jump to: navigation, search

A DNS sinkhole, also known as a sinkhole server, Internet sinkhole, or BlackholeDNS[1] is a DNS server that gives out false information[clarification needed], to prevent the use of a domain name.


A sinkhole does not need to be a large DNS server, it only needs to be in the DNS lookup chain.[clarification needed]

Network-level disabling[edit]

A sinkhole is a standard DNS server that has been configured to hand out non-routable addresses for all domains in the sinkhole, so that every computer that uses it will fail to get access to the real website.[2] The higher up[clarification needed] the DNS server is, the more computers it will block. Some of the larger botnets have been made unusable by TLD sinkholes that span the entire Internet.[3] DNS Sinkholes are effective at detecting and blocking malicious traffic, and are used to combat bots and other unwanted traffic.

Host-level disabling[edit]

The local hosts file on a Microsoft Windows, Unix or Linux computer is checked before DNS servers, and can also be used to block sites in the same way.


Sinkholes can be used both constructively, as has been done for the containment of the WannaCry threat,[4] and destructively, for example disrupting DNS services in a DoS attack.

One use is to stop botnets, by interrupting the DNS names the botnet is programmed to use for coordination. The most common use of a hosts file-based sinkhole is to block ad serving sites.[5]


  1. ^ kevross33, pfsense.org (November 22, 2011). "BlackholeDNS: Anyone tried it with pfsense?". Retrieved October 12, 2012. 
  2. ^ Kelly Jackson Higgins, sans.org (October 2, 2012). "DNS Sinkhole - SANS Institute". Retrieved October 12, 2012. 
  3. ^ Kelly Jackson Higgins, darkreading.com (October 2, 2012). "Microsoft Hands Off Nitol Botnet Sinkhole Operation To Chinese CERT". Retrieved September 2, 2015. 
  4. ^ https://gist.github.com/rain-1/989428fa5504f378b993ee6efbc0b168
  5. ^ Dan Pollock, someonewhocares.org (October 11, 2012). "How to make the Internet not suck (as much)". Retrieved October 12, 2012.