ECSeptional DNS Data: Evaluating Nameserver ECS Deployments with Response-Aware Scanning - ECS Scan Results

DNS is one of the cornerstones of the Internet. Nowadays, a substantial fraction of DNS queries are handled by public resolvers (e.g., Google Public DNS and Cisco’s OpenDNS) rather than ISP nameservers. This behavior makes it difficult for authoritative nameservers to provide answers based on the requesting resolver. The impact is especially important for entities that make client origin inferences to perform DNS-based load balancing (e.g., CDNS). The EDNS0 Client Subnet (ECS) option adds the client’s IP prefix to DNS queries, which allows authoritative nameservers to provide prefix-based responses. Previous work showed the potential of data collected during ECS scans. Infrastructure can be uncovered and subnet specific behavior of operators can be observed.