You mean, all of the NTP servers the machine uses. NTP will detect and reject a single server reporting bad time (assuming you have at least 3 servers configured, which is the recommendation).
You'd also have to do this when the NTP daemon first starts up, as:
-g Normally, ntpd exits with a message to the system log if the offset exceeds the panic
threshold, which is 1000 s by default. This option allows the time to be set to any value
without restriction; however, this can happen only once. If the threshold is exceeded after
that, ntpd will exit with a message to the system log. This option can be used with the -q
and -x options. See the tinker command for other options.
The NTP config on the machine would have to allow automatic changes without regard to the skew. I don't believe that is a default (or typically desired) configuration.
