Sep 28 – 29, 2020 AGM
UTC timezone

DNS Shotgun: realistic DNS resolver benchmarking (also) for stateful transports

Sep 28, 2020, 4:00 PM
Standard Presentation Online Workshop OARC 33 Day 1


Petr Špaček (CZ.NIC)


In this talk we introduce measurement tool called "DNS Shotgun". DNS Shotgun is a open-source tool for near-real-world benchmarking DNS resolvers. The tool reads a traffic capture with real client query streams. Then, the behavior of clients can be customized - including the choice of DNS-over-UDP/TCP/TLS/HTTPS2 protocols and connection parameters. Finally, the tool replays the original queries over the selected protocols, while keeping a realistic query timing (and cache hit rate). This approach removes problematic step "guess & describe how I believe my clients behave" from the benchmarking process which is required by traditional approaches to benchmarking, and thus gives results closer to reality.

In the end this method allows much better assessment of costs involved in transitioning DNS traffic to stateful protocols and enable better capacity planning based on measurements.

Together with scripts for data analysis the tool enables us to answer complex questions about changes in client behavior, e.g.: Can my DNS resolver system provide reliable and responsive resolution service if 50 % of my clients switch from plain UDP to DoT and reuse connections for 10 seconds since last query?

Through the talk we also describe necessary tuning parameters and scaling problems we encountered.

Postponement (Please leave blank)

  • [Jan] September date works for the speaker.

  • Any option is fine (barring unforeseen circumstances).
    if doing a remote presentation for virtual mini-OARC or other OARC activity at any time will need significant time to prepare the talk as need to process a lot of data.

Talk Duration 20 minutes

Primary author

Petr Špaček (CZ.NIC)

Presentation materials