researchtoolssurveys DNSFactory


Open Resolvers

Past surveys that searched for open DNS resolvers.

IPv6 Survey (October 2011)

We measured IPv6 deployment statitistics from DNS point of view, taking a 1% (1.2M names) sample of domain names in the .com, .net, and .org zones and investigating to what extent IPv6 has been deployed for key services associated with each domain.

Number of Nameservers (April 2005)

We probed 5% of routed IPv4 space, or 70 million addresses, looking for nameservers. For those that replied, we also tried to determine their software and version.

Zone and Nameserver Statistics

With these surveys we send queries to 1,000,000+ zones and their authoritative nameservers looking for zones and nameservers that:

  • Advertise their software version
  • Allow recursion
  • Allow zone transfers
  • Exist on the same subnet
  • Have delegations which differ from authoritative NS records
  • Have lame delegations
  • Have questionable SOA and TTL values
  • Have mismatched serial numbers
  • Utilize IPv6
  • Utilize DNSSEC
  • Publish SPF records or have DKIM configured
  • Support 0x20

We also query a random 5% sample of routed IP addresses to look recursive resolvers and determine whether or not they openly provide service to anyone, and what software they are running.

Cache Poisoners

A survey that searched for DNS cache poisoners.

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