Mark Felder <f...@freebsd.org> writes: > I'm not an expert on the leapsecond operation, but if I understand it > correctly there are two ways a system can be notified of a leapsecond: > via a tzdata update or through NTP.
Answering a bit late, but no: in practical terms, only NTP works. Recording leap seconds in tzdata breaks POSIX and a lot of assumptions in existing code, not only on the day a leap second occurs but at any time in history after at least one leap second has occurred. > 1) FreeBSD server unaware of leapsecond due to no tzdata entry and not > synced to NTP ends up 1 second off A server which is not synchronized with a reliable external source will end up a lot more than one second off regardless of leap seconds, because it relies solely on onboard RTCs and oscillators which are both inaccurate and imprecise. Clock drift will be measured in seconds per week and vary depending on CPU load, disk I/O, the phase of the moon and your dog's horoscope. > 2) FreeBSD server unaware of leapsecond due to no tzdata entry synced to > leapsecond-aware NTP server successfully handles leapsecond Correct. > 3) FreeBSD server unaware of leapsecond due to no tzdata entry acting as > NTP server doesn't notify clients of leapsecond and they end up 1 second > off This assumes that the hypothetical server is not synchronized with a reliable external source, which is a broken setup to begin with (see 1). DES -- Dag-Erling Smørgrav - d...@des.no _______________________________________________ freebsd-security@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-security To unsubscribe, send any mail to "freebsd-security-unsubscr...@freebsd.org"
