DNS Performance and the Effectiveness of Caching
This paper presents a detailed analysis of traces of DNS and associated TCP traffic collected on the Internet links of the MIT Laboratory for Computer Science and the Korea Advanced Institute of Science and Technology (KAIST). The first part of the analysis details how clients at these institutions interact with the wide-area domain name system, focusing on client-perceived performance and the prevalence of failures and errors. The second part evaluates the effectiveness of DNS caching. In the most recent MIT trace, 23% of lookups receive no answer; these lookups account for more than half of all traced DNS packets since query packets are retransmitted overly persistently. About 13% of all lookups result in an answer that indicates an error condition.