Check a list of hosts (candidates) for reliable public DNS resolvers. Reliable means responding correctly to queries.
Initial use case is for finding a large number of open DNS resolvers for quick subdomain discovery using a parallel resolver tool such as blechschmidt's massdns. This software will send very few packets to each host so as to be minimally invasive.
Don't be evil if you use this software. If you are malicious, no one is responsibel but yourself.
Provided by mzpqnxow's public-dns-resolvers project. Not privy to the original source, but mzpqnxow claims a public source.
sudo setcap CAP_NET_RAW+ep /usr/bin/masscan