Where does the value for the timestamp come from on the server (for example, for the time() php function)?

Question

PHP

Synchronization? With what? How often?

Answer 1

About with whom and how to synchronize: https://habrahabr.ru/post/79461/
Details, including how often: vasilisc.com/time-server-ntp
And of course an article from Wikipedia , where learn how timedtamp is obtained:

Time is represented in the NTP system by a 64-bit number (8 bytes) consisting of a 32-bit second counter and a 32-bit fractional second counter, allowing time to be transmitted in the range of 232 seconds, with a theoretical accuracy of 2-32 seconds. Since the time scale in NTP repeats every 232 seconds (136 years), the recipient must at least roughly know the current time (with an accuracy of 68 years[8]). Also keep in mind that the time is counted from midnight on January 1, 1900, and not from 1970, so almost 70 years (including leap years) must be subtracted from the NTP time in order to correctly align the time with Windows or Unix systems.

Answer 2

And where does the time on your local computer come from? It's the same on the server. https://ru.wikipedia.org/wiki/NTP
With what exactly and how often it is synchronized - see the OS settings. https://ru.wikipedia.org/wiki/Ntpd