Regarding the dhcp lease time

Simon Hobson dhcp1 at
Wed May 8 10:47:52 UTC 2019

Just to add, AFAIR lease times in the packets on the wires are just durations in seconds. So if both server and client clocks are stable then any offset doesn't matter at all - each will work relative to it's own time.

It's the change in server clock that's the problem. *Changing* the time on a server (apart from simple correction to keep it accurate) is generally "a bad thing" and can break all sorts of things.

As an aside, I once worked with an OS (Apollo Domain) where (IIRC) file inodes were a combination of the machine's MAC address and clock time at the point of file creation. Changing a network card or moving a hard disk between nodes meant running a program to change the MAC address part of all inodes, but setting the clock backwards was a real "just don't do it" thing due to the problems it could create with duplicate inode numbers.

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