4 ms·

I wouldn't shy away from serving SNTP from virtualized Windows domain controllers nowadays--it's okay for its designed purpose, although "good" time probably in

by sk5t 9y ago

I wouldn't shy away from serving SNTP from virtualized Windows domain controllers nowadays--it's okay for its designed purpose, although "good" time probably involves appliances / GPS or somesuch radio devices.

toomuchtodo 9y ago
You can do it with a GPS receiver and a Raspberry Pi for ~$80. https://www.ntpsec.org/white-papers/stratum-1-microserver-howto/ https://www.ntpsec.org/white-papers/stratum-1-microserver-ho... http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html https://hackaday.io/project/15137/instructions https://hackaday.io/project/15137/instructions Otherwise, if you're not interested in running your own hard, just use the NTP Pool service: http://www.pool.ntp.org/en/ http://www.pool.ntp.org/en/
- sk5t 9y ago
  Aye, all good and worthy things. A Windows domain, however, typically establishes its own hierarchical time system (PDCe -> RWDCs (+ clients) -> RODCs (+ clients)), with only the PDCe relying on external time sources. Windows SNTP is not really designed for high precision/high accuracy anyway, so, you just kinda go "meh good enough" not too far into the adventure. Also the time management CLI tools stink.
  - deleted 9y ago
    [deleted]
  - hug 9y ago
    Whoever was responsible for naming the service "w32time" and naming the command to manage the configuration of that service "w32tm" should be fired out of a cannon into the sun.
- asdfaoeu 9y ago
  I feel like the subset of computing applications that require accurate time doesn't intersect with the amount of applications where you want to rely on a raspberry pi and can get signals directly from a satellite (i.e. not in a DC). A more practical example would probably just be to find a professionally hosted stratum 1 server to sync off.
- Already__Taken 9y ago
  Does this still work ok if GPS goes off?
  - toomuchtodo 9y ago
    You'll have drift if GPS is down. Then again, if GPS is down, your time server's drift is probably the least of your concerns.
    - wbl 9y ago
      GPS reception can vary for reasons short of thermonuclear war. TXCO slaves are not that expensive.
    - Already__Taken 9y ago
      These things do happen albeit fairly targeted https://www.ofcom.org.uk/spectrum/information/gps-jamming-exercises https://www.ofcom.org.uk/spectrum/information/gps-jamming-ex...
xenophonf 9y ago
w32time supports proper NTP (albeit NTPv3), and Windows Server 2016/Windows 10 Anniversary is capable of 1-millisecond accuracy: https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/get-started/windows-time-service/windows-2016-accurate-time https://docs.microsoft.com/en-us/windows-server/identity/ad-... But if that isn't good enough for you, you can easily replace w32time with the reference NTP implementation, which is what I do to all of my Hyper-V hosts and physical forest root PDCs: https://www.meinbergglobal.com/english/sw/ntp.htm https://www.meinbergglobal.com/english/sw/ntp.htm

by sk5t 9y ago

toomuchtodo 9y ago

You can do it with a GPS receiver and a Raspberry Pi for ~$80. https://www.ntpsec.org/white-papers/stratum-1-microserver-howto/ https://www.ntpsec.org/white-papers/stratum-1-microserver-ho... http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html https://hackaday.io/project/15137/instructions https://hackaday.io/project/15137/instructions Otherwise, if you're not interested in running your own hard, just use the NTP Pool service: http://www.pool.ntp.org/en/ http://www.pool.ntp.org/en/

sk5t 9y ago
Aye, all good and worthy things. A Windows domain, however, typically establishes its own hierarchical time system (PDCe -> RWDCs (+ clients) -> RODCs (+ clients)), with only the PDCe relying on external time sources. Windows SNTP is not really designed for high precision/high accuracy anyway, so, you just kinda go "meh good enough" not too far into the adventure. Also the time management CLI tools stink.
- deleted 9y ago
  [deleted]
- hug 9y ago
  Whoever was responsible for naming the service "w32time" and naming the command to manage the configuration of that service "w32tm" should be fired out of a cannon into the sun.
asdfaoeu 9y ago
I feel like the subset of computing applications that require accurate time doesn't intersect with the amount of applications where you want to rely on a raspberry pi and can get signals directly from a satellite (i.e. not in a DC). A more practical example would probably just be to find a professionally hosted stratum 1 server to sync off.
Already__Taken 9y ago
Does this still work ok if GPS goes off?
- toomuchtodo 9y ago
  You'll have drift if GPS is down. Then again, if GPS is down, your time server's drift is probably the least of your concerns.
  - wbl 9y ago
    GPS reception can vary for reasons short of thermonuclear war. TXCO slaves are not that expensive.
  - Already__Taken 9y ago
    These things do happen albeit fairly targeted https://www.ofcom.org.uk/spectrum/information/gps-jamming-exercises https://www.ofcom.org.uk/spectrum/information/gps-jamming-ex...

xenophonf 9y ago

w32time supports proper NTP (albeit NTPv3), and Windows Server 2016/Windows 10 Anniversary is capable of 1-millisecond accuracy: https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/get-started/windows-time-service/windows-2016-accurate-time https://docs.microsoft.com/en-us/windows-server/identity/ad-... But if that isn't good enough for you, you can easily replace w32time with the reference NTP implementation, which is what I do to all of my Hyper-V hosts and physical forest root PDCs: https://www.meinbergglobal.com/english/sw/ntp.htm https://www.meinbergglobal.com/english/sw/ntp.htm