BIND. From its DESCR:
This is queryperf, a DNS server query performance testing tool.
It is primarily intended for measuring the performance of
authoritative DNS servers, but it has also been used for measuring
caching server performance. This document describes the use of
queryperf for authoritative server performance testing.
NOTE: This version of queryperf has been modified by Nominum. It
implements a slow-start algorithm which lessens the risk of network
buffer overflows, particularly when testing recursive servers
with high values for the -q option.
