A Method to Generalize DNS TTL Value Calculation

Abstract

The domain name service (DNS) is the service that resolves IP address(es) for a given fully qualified domain name (FQDN). The DNS is implemented as a hierarchical distributed cache system that stores the IP addresses of the FQDNs for a certain amount of time which is specified in time to live (TTL) value. The TTL value is a arbitrary value set by the authoritative name servers, aka service providers, and hence, the calculation of the TTL value is not defined in any literature the authors referred incurring that calculation of the TTL value is a mysterious part about the DNS service. To this end, this paper proposes a generalized method to calculate the TTL value of the DNS record using the performance of web server (i.e., authoritative name server) where an actual web request has to wait to until it is get served. This paper explains the proposed mathematical method of calculating the TTL values of DNS records and provides a detailed explanation of the used parameters with the reasons of selecting those parameters to calculate the TTL value.