Measuring availability in the domain name system

Abstract—The domain name system (DNS) is critical to Inter-net functionality. The availability of a domain name refers to its ability to be resolved correctly. We develop a model for server dependencies that is used as a basis for measuring availability. We introduce the minimum servers queried (MSQ) and redundancy as availability metrics and show how common DNS misconfigu-rations impact the availability of domain names. We apply the availability model to domain names from production DNS and observe that 6.7 % of names exhibit sub-optimal MSQ, and 14% experience false redundancy. The MSQ and redundancy values can be optimized by proper maintenance of NS RRs for zones. I