"What's the one thing that you see criminals, spies and other
mysterious individuals doing just prior to embarking on a caper? If
you said, "synchronize their watches" you guessed correctly. And,
why do they do it? Because timing is everything. The Network Time
Protocol (NTP) does the same thing for your systems and for the
same reasons; it keeps them synchronized.
"Why is system time synchronization so important? If you've ever
seen the message, "modification times are in the future" or had the
misfortune to have your SAN or network attached storage deny access
to a system or user account because of a time sync problem, you
know why. Time sychronization is also important when you need to
compare logged events between a system and a network device."