DNS Measurements

The core of our observatory are DNS measurements to discover a large set of publicly reachable infrastructure (e.g., web servers). We therefore regularly resolve over 50% of the global domain name space. We then probe all discovered hosts for HTTP2, QUIC, TCP IW, or CAA support and configuration.

Besides our additional protocol probes (e.g., for QUIC), the DNS data alone is a rich data set to study the Internet evolution. As one example, we used the Mail Exchange (MX) of each known domain to study the evolution cloud email services (watch Martins talk at TMA'17 on YouTube). The measurements enabled us to discuss potential privacy implications for Internet-users by hidden cloud email usage.

TLD Zone Coverage

We obtain complete zone files for .com, .net, .org, .fi, .se, .nu, .gov, .fed.us, .name, and over 1000 new gTLDs (e.g., .london) on a daily basis.

Besides these TLDs for which we obtain complete zone files, we have incomplete domain lists for more than 80 ccTLDs (e.g., .de) that we obtain from passive and active measurements.

DNS Resolutions per Domain

For each second level domain name (i.e., domain.tld), we probe for the following resource records:

  1. ANY
  2. SOA
  3. CAA
  4. LOC
  5. A for domain.tld and www.domain.tld
  6. AAAA for domain.tld and www.domain.tld
  7. NS and A + AAAA for every NS record
  8. MX and A + AAAA for every MX record