The Japan Computer Emergency Response Team Coordination Center (JPCERT/CC) has launched a new service that allows users to check if they’re running an open DNS resolver, a publicly accessible name server that provides a recursive name resolution for unspecified IPs.In October 2013, experts found around 28 million open DNS resolvers worldwide. The problem with these servers is that they’re being abused for distributed denial-of-service (DDOS) attacks.
The Open DNS Resolver Check Site launched by JPCERT/CC allows users to check if the DNS server on their PC, or their network device, is running an open DNS resolver.
If an open DNS resolver is detected, the user is provided with instructions on how to properly configure the server or the network device.
Test your own configuration on the Open DNS Resolver Check Site. The service is available in English and Japanese.