There is a way to add ntp-server dhcp option request in a windows clients?
In the registry it ask some option but not ntp.
Thanks in advance
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What are you actually trying to do?– DavidPostill ♦Commented Mar 9 at 7:43
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Feels like a potential dupe of this superuser.com/questions/147248/…– Journeyman Geek ♦Commented Mar 9 at 8:32
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reddit.com/r/PFSENSE/comments/o2cc09/… also seems to suggest support for it is pretty bad in general– Journeyman Geek ♦Commented Mar 9 at 8:34
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1 Answer
It seems that NTP over DHCP is (mostly) unused, especially perhaps under Windows. Below are some partial quotes from some discussions about the reason for it.
NTP over DHCP - why does nothing actually use it?
The only devices we have on our network that actually listen to ntp servers being set via dhcp are thin clients. And even then once they connect to the central management server they get new ntp servers which the terminals sync from. There are tons of dhcp options which are pretty much ignored (nntp, smtp). Honestly I’m surprised most devices still honor option 121 for static routes.
DHCP is pretty awful. Clients will cache results (as a defense against bad/slow DHCP servers), not renew on the DHCP schedule, get sloppy with interpreting fields because the spec wasn't clear (strings v IPs v who knows), fail to get a response when roaming, etc. etc. It also assumes that you trust the config you're getting - should a coffee shop wifi be allowed to set the clock on a corporate laptop (and potentially force password expiry, kill the machine on its domain, etc.)?
As a result, systems have been built in ways to be defensive against DHCP. We need it, because it's the only widely accepted auto address allocation system (until IPv6 takes root), but as soon as that address is allocated - most sane network management tools will then use that link to communicate all the real info. For NTP, this can involve getting resync times, info about timezone, info about secondary servers (and how to fail over), info about maximum drift sizes, etc.
DHCP was this be-all-end-all protocol for network config, but its design doesn't allow for the kinds of rich config data we use these days. As a result, the industry has taken the sane path - DHCP does what it's good at, and everything else flows from there.
DHCP Options 4,42 not being served
From what I know, older version Windows (e.g. Win7) and MacOS doesn't support time/NTP option from DHCP server, this is decided by DHCP client so you can do nothing about it. And this has security concerns because when someone created another DHCP on network with an incorrect time/NTP settings then your device time settings will be messed up.
