Quantitative evaluation model of DNS resolvability based on propositional logic

To solve the problem of quantitative evaluation of DNS resolvability, a method for quantitative evaluation of DNS resolvability based on propositional logic is presented below: establishing the dependence relation graph of domain name resolution through analyzing the dependence of domain name resolution, and transforming the dependency of a domain on a DNS server into a logic graph using the propositional logic; finding the smallest name-resolvable DNS server set through the proposition formulae's DNF (disjunctive normal form) transformation and the analysis of the simple CNF (conjunctive normal form) with the minimum number of propositional variations to direct the layout of servers; making proposition formulae's CNF transformation and the analysis of the simple DNF with the minimum number of propositional variations to find the smallest name-resolvable DNS servers to emphatically protect the DNS servers. Based on the analysis of the Alex top 1000 domain, it can be found by statistical calculation that the average dependent DNS number of resolution in Alex Top 1000 is 5.58, the mini-number servers of domain resolution are in [1, 4] with the average number of 1.41, and the mini-number servers of damaging domain resolution are in [1, 6] with the average number of 2.44.