Computer Time Synchronization
A Beginner's Guide to Network Time Protocol (NTP)
Note: This page is still accurate.
I hope that you've found these pages a useful introduction to NTP. When I
first found the University of Delaware NTP
site, I found the quantity
of information somewhat intimidating but am glad I spent the time necessary
to get NTP servers and clients running on my various systems. I'v never
learned about the many NTP options
including the authentication, monitoring and access control options that
I've completely ignored here as well as what the ntpq, query program
As a practical matter though, I accomplished my original
goal of synchronized time on all my computers as well as the optional
goal of accurate time. Its authors describe ntpd as "fat" but its memory
footprint is less than half a megabyte and there is
no perceptible CPU load.
After a lifetime of calling the local phone company's
time service to set a variety of clocks, watches and time sensitive
devices, it's really nice to have local time sources that will always
be much more accurate than the phone company. Since I started investigating
time synchronization software, I learned that the phone company
time was consistently about ten seconds off. The phone company has not
provided this service for some years now.
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