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Re: [Ntp] Antw: Re: Antw: [EXT] Local time in NTPv5?

Miroslav Lichvar <mlichvar@redhat.com> Mon, 01 August 2022 08:13 UTC

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Date: Mon, 01 Aug 2022 10:13:52 +0200
From: Miroslav Lichvar <mlichvar@redhat.com>
To: Hal Murray <halmurray@sonic.net>
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Subject: Re: [Ntp] Antw: Re: Antw: [EXT] Local time in NTPv5?
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On Fri, Jul 29, 2022 at 09:27:41AM -0700, Hal Murray wrote:
> Is there a tool for poking at DHCP servers to see what they provide?  I poked 
> around a bit but diddn't find one.
> 
> I scanned the man page for the ISC DHCP server and didn't find any mention of 
> NTP or time zones.  (ntp was mentioned as a logging option.)

It seems to be configured by the pcode option, documented in
dhcp-options(5).

With dnsmasq it's enabled by dhcp-option=100,"...".

> If a client gets its IP Address from a server, does it latch on to that server 
> and ignore others?

I think it depends on the system/client. The scripts that some Linux
distributions have add the NTP servers from DHCP to the existing
NTP configuration and there is an option to specify the NTP server
options, so the servers from DHCP could be trusted or preferred over
the others servers.

> Or will it try broadcasting to find other servers before 
> giving up?  Can we setup a DHCP server that only provides time zone info?

-- 
Miroslav Lichvar

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