Taming DNS Responses: A Measurement Study of Response Size and Its Impact#

Authors: Zihan Li, Wenhao Wu, Zhaohua Wang, Yu Tian, Chuan Gao, Qinxin Li, Yiming Xia, Zhenyu Li (Chinese Academy of Sciences)

• Why: DNS is increasingly a carrier for structured metadata and service-discovery data, and that growth directly feeds UDP amplification risk. If you operate resolvers or reason about DDoS surface, the global response-size picture matters.
• What: A year-long measurement of response-size behavior across roughly one million open resolvers. Findings: resolver-enforced UDP response-size limits cluster around a small set of common values; configuration changes at major public resolvers propagate across the ecosystem; and regional differences in limits create uneven amplification risk, exposing limits of existing static and upstream-based defenses. Proposes Adaptive Response Scaling (ARS), a lightweight dynamic response-control mechanism claimed to reduce amplification by over 70% while preserving DNS functionality. (from abstract only)
• How: Longitudinal measurement of resolver response-size limits across the open-resolver population, plus analysis of how major-resolver configuration changes propagate.
• Where applicable: DNS operators and public resolvers broadly. ARS is a proposal evaluated by the authors, not a deployed standard — the measurement findings are solid ground, the mitigation is directionally promising.