Re: [dhcwg] [ntpwg] Fwd: New Version Notification for draft-ogud-dhc-udp-time-option-01.txt

Harlan Stenn <stenn@ntp.org> Wed, 04 December 2013 01:40 UTC

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From: Harlan Stenn <stenn@ntp.org>
To: Kurt Roeckx <kurt@roeckx.be>
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References: <20131202044734.B78E0406060@ip-64-139-1-69.sjc.megapath.net> <529C1A31.2080900@ntp.org> <258D838F-F4BA-45D2-AA41-BB05E3AB147C@ogud.com> <20131203124925.GE2329@roeckx.be>
Comments: In-reply-to Kurt Roeckx <kurt@roeckx.be> message dated "Tue, 03 Dec 2013 13:49:25 +0100."
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Date: Wed, 04 Dec 2013 01:40:17 +0000
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Cc: Hal Murray <hmurray@megapathdsl.net>, Bernie Volz <volz@cisco.com>, NTP Working Group <ntpwg@lists.ntp.org>, Ted Lemon <ted.lemon@nominum.com>, "dhcwg@ietf.org WG" <dhcwg@ietf.org>
Subject: Re: [dhcwg] [ntpwg] Fwd: New Version Notification for draft-ogud-dhc-udp-time-option-01.txt
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Kurt Roeckx writes:
> > 	 settimeofday(const struct timeval *tp, const struct timezone *tzp)
> 
> I don't think that is something we want every dhcp client to do.
> If ntpd is running you really don't want something else to change
> the time.

There is a difference between DHCP at startup and a DHCP "refresh".

I suspect that a DHCP refresh should leave the clock alone.

For the startup case:

I think the best solution to this problem for LAN-connected devices will
turn out to be PTP.  And if that is not available, if you can't trust
your DHCP server to tell you what time it is, why would you trust it to
give you an IP address?

H