Theo de Raadt ( deraadt@ ) posted to tech@:

The ntpd options -s and -S are going to be removed soon and at startup with print: -s option no longer works and will be removed soon. Please reconfigure to use constraints or trusted servers. Probably after 6.7 we'll delete the warning. Maybe for 6.8 we'll remove -s and -S from getopt, and starting with those options will fail. Effective immediately, the -s option stops doing what you expect. It now does nothing. Big improvements have happened in ntpd recently. At startup, ntpd aggressively tries to learn from NTP packets validated by constraints, and set the time. That means a smarter variation of -s is the default, but the information is now *VALIDATED* by constraints. 2 additional constraints have been added. If you have upgraded, please review /etc/examples/ntpd.conf for modern use Those who cannot use https constraints, can instead tag server lines with the keyword "trusted", which means you believe MITM attacks are not possible on the network to those specific NTP servers. Do this only on servers directly connected over trusted network. If someone does "servers pool.ntp.org trusted", we're going to have a great laugh. We're creating something a bit complex, but our goal is for every machine to have a close approximation of correct time. If we get there, some good things will happen. Some serious cargo-culting for using -s has gotten in the way (-s performs no MITM checks).