Steve Kostecke <[email protected]> writes: >On 2009-01-26, [email protected] <[email protected]> wrote:
>> I have a network isolated the internet but I need a time server to run >> on this private network. Are there any standalone time server packages >> out there? Is there a way to force ntpd to sync with my computer clock >> and then run sending out the time data? >NTP is designed to synchronize computer clocks to a common time-base. >The most frequently used time-base is UTC; usually acquired over a >network. But others can be substituted. >In the absence of a proper time-base you _can_ use the Undisciplined >Local Clock or Orphan Mode to allow your ntpd to claim to be >synchronized to a time source >You have a number of choices for the acquisition of a time-base: >1. Use a radio clock (e.g. GPS) as suggested elsewhere in this thread >2. Use a modem to dial-up the ACTS time service at NIST >3. Use a high-quality (e.g Rubidium) oscillator / frequency reference to >feed PPS or IRIG to your time server >4. Use dumb-clock to obtain time stamps over a serial link from a >properly synchronized local time server >If you wish to operate your time island without a proper time-base >there are some steps that you can take to maximize time stability: >1. Dedicate one computer as a time server. This time server should _not_ >be running Windows. An old Pentium-1 is more than adequate >2. Connect this server to a network in an environment which is similar >to that of the time island and configure it to poll 4 remote time >servers (see http://support.ntp.org/s2 to choose servers). Let your time >server run for at least 24 hours so that ntpd is able to calculate an >approximate frequency correction >3. Reconfigure the time server to use the Undisciplined Local Clock (or, >if you are using a recent enough version of NTP, Orphan Mode) and move >the system to the time island >4. Use ntpdc to manually trim the frequency offset when your time island >drifts visibly from wrist-watch time You can also use chrony. It has an explicit mode in which you type in the time every once in a while from your wristwatch and it uses that to discipline the local clock. It must be run under Linux, and it cannot use a "Hardware" clock (gps, rubidium,etc) but can use modem, or any network time source, and it can use wristwatch time to discipline the local clock. Obviously you cannot expect better than a few seconds accuracy from something like this. That chrony machine can act as a server to other ntp or chrony systems as well. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
