MIT implemented NTP rate-limiting to defend against on-going reflection attacks,
which was causing our nagios checks to fail intermittently. When the attacks
die down or when external sites fix their NTP configurations, checking against
time.mit.edu will stop failing. However, there also isn't much of a reason to
stick with checking against a single server.
(imported from commit 2c2a1a04646b880b010cbb4b6d94016b1eccd1a0)
Zev Benjamin
Tim Abbott
acrefoot