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

Hi!

I wonder whether BCP-43  may be relevant. I found a manual page stating:

       option ntp-servers ip-address [, ip-address...  ];

         This  option  specifies  a  list of IP addresses indicating NTP (RFC
         5905) servers available to the client.  Servers should be listed  in
         order of preference.

       option tcode text;

         This option specifies a name of a zone entry in the TZ database.

         This option is included based on RFC 4833.

       option dhcp6.new-posix-timezone text;

         This option specifies a string suitable for the TZ variable.

         This option is included based on RFC 4833.

       option dhcp6.new-tzdb-timezone text;

         This option specifies a name of a zone entry in the TZ database.

         This option is included based on RFC 4833.

RFC-4833 is "Timezone Options for DHCP" (April, 2007)

Regards,
Ulrich

>>> James <james.ietf@gmail.com> schrieb am 01.08.2022 um 00:55 in Nachricht
<BF45EFF3-E992-4C4E-BB80-78061B60678F@gmail.com>:
> Danny,
> It would be very much appreciated if you could dig out the RFC number or 
> point to wherever DHCP specification, because I'm unable to find reference
to 
> anything that may hint, noting that the IANA registries for DHCP and DHCPv6

> options, there is RFC 5908 mentioned which covers DHCPv6, but I am unable to

> find anything in reference to DHCPv4 ‑ all that appears immediately obvious
is 
> Tag 4, which refers to RFC 2132, which in turn refers to the Time Protocol 
> defined in RFC 868.
> 
> ‑ J
> 
>> On 1 Aug 2022, at 00:27, Danny Mayer <mayer@pdmconsulting.net> wrote:
>> 
>> 
>> On 7/29/22 12:27 PM, Hal Murray wrote:
>>> mlichvar@redhat.com said:
>>>> You mean the TZ POSIX string (option 100) from RFC4833? That looks like
it
>>>> could work, even for announcing the DST change.
>>>> So, I guess the question is now are there any use cases for the local
time 
> in
>>>> NTP without DHCP?
>> That's irrelevant. NTP knows nothing about time zones.
>>> That only works if the DHCP servers in use actually support it.
>>> 
>>> 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.)
>> 
>> DHCP supports NTP server provisioning. I worked with the DHCP WG on it a 
> number of years ago. I don't know the RFC number.
>> 
>> 
>>> If a client gets its IP Address from a server, does it latch on to that 
> server
>>> and ignore others?  Or will it try broadcasting to find other servers
before
>>> giving up?  Can we setup a DHCP server that only provides time zone info?
>>> 
>> Read the DHCP RFCs. I don't know if there is provisioning for time zones.
>> 
>> Danny
>> 
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