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A comment on Windows feature that resets system clocks based on random data is wreaking havoc. Parent comment

Re:Windows feature that resets system clocks based on random... by tedunangst on Wednesday August 16, 2023 @03:01PM (#37151973)
Openbsd does an https (with expiry checks disabled) GET to google.com (or another server) and uses the Date header in the response.
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Re:Windows feature that resets system clocks based on random... by JohnFen on Wednesday August 16, 2023 @03:51PM (#37152730)
If it's assuming that it can make an internet connection, why does it do that rather than NTP?
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Re:Windows feature that resets system clocks based on random... by somat on Wednesday August 16, 2023 @04:07PM (#37152960)
It is a sanity check to protect against malicious ntp actors.

http://man.openbsd.org/ntpd.conf#CONSTRAINTS

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Re:Windows feature that resets system clocks based on random... by toast0 on Wednesday August 16, 2023 @03:59PM (#37152852)
NTP is trivially MITM. Secure NTP is basically not deployed anywhere. Someone with a google.com cert that's valid other than expiration is probably google and probably has a working clock.
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Re:Windows feature that resets system clocks based on random... by anthk on Wednesday August 16, 2023 @04:03PM (#37152908)
You can always use a gpsd(4) compatible USB dongle as the time source.
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Re:Windows feature that resets system clocks based on random... by toast0 on Wednesday August 16, 2023 @04:13PM (#37153060)
Sure, if you have such a dongle, and it has sufficient view of the sky. Adding a 'free' https based sanity check on top of NTP seems like a good balance of cost vs reward.

gps (and friends) is a nice way to get access to a very accurate timesource, but it's not always worth the cost.

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Re:Windows feature that resets system clocks based on random... by JohnFen on Wednesday August 16, 2023 @04:09PM (#37152994)
Or run their own NTP server. That's what I do in my home network.
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Re:Windows feature that resets system clocks based on random... by labawi on Sunday August 20, 2023 @02:01PM (#37201495)
GPS doesn't send full time. It wraps every 1024 weeks, or about 20 years, hence you need a (very) rough basis in case the system is over 20 years old.
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