Benchmarking Authoritative DNS Servers

In this paper, we examine the performance of four authoritative DNS server implementations (BIND, NSD, Knot DNS, and YADIFA). In our tests, we apply the measurement procedure defined in Section 9 of RFC 8219. Our aim is threefold: to provide DNS operators with ready to use measurement results to support their selection of the best fitting authoritative DNS server implementation for their needs, to assist researchers and DNS64 server developers in finding a suitable authoritative DNS server implementation for their DNS64 benchmarking measurements, and to advance the theory and practice of benchmarking DNS servers. We examine how the different conditions such as the number of active CPU cores, the size of the zone file, the applied timeout, and the type of the processor influence the performance of the tested authoritative DNS server implementations. The performance of all four tested DNS servers scales up more or less well with the number of CPU cores, except for YADIFA. The increase of the size of the zone file causes significant degradation only in the performance of BIND, which shows different anomalies described in the paper. The change of the timeout from 250ms (required by RFC 8219) to 100ms usually causes only a small performance degradation. We point out that NSD and Knot DNS can achieve an order of magnitude higher performance than BIND and YADIFA.