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Groups > linux.debian.user > #264350

Re: ntpsec as server questions

From Greg Wooledge <greg@wooledge.org>
Newsgroups linux.debian.user
Subject Re: ntpsec as server questions
Date 2023-12-06 19:30 +0100
Message-ID <HI4OK-bLIF-9@gated-at.bofh.it> (permalink)
References (5 earlier) <HHSDT-bBsb-1@gated-at.bofh.it> <HI3fX-bKeG-1@gated-at.bofh.it> <HI4c2-bL69-5@gated-at.bofh.it> <HI4lH-bLc9-13@gated-at.bofh.it> <HI4vn-bLxi-11@gated-at.bofh.it>
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On Wed, Dec 06, 2023 at 01:02:45PM -0500, Pocket wrote:
> TZ=POSIX;date
> Wed Dec  6 18:00:38 POSIX 2023

"POSIX" is not a valid timezone name in Debian 12.  Therefore you're
just seeing UTC here.  Giving an invalid TZ always gives you UTC, but
with whatever crazy-ass name you used echoed back at you, to give you
the illusion that your name was valid.  It's a *huge* pitfall.  I've been
bit by this myself.

> TZ=America/New_York;date
> Wed Dec  6 13:00:21 EST 2023
> 
> TZ=EST5DST;date
> Wed Dec  6 13:01:10 EST 2023
> 
> What is the problem?

Gods DAMN it.  I didn't want to have to dig through these stupid zone
dumps, but you're FORCING my hand.

unicorn:~$ zdump -v -c 1918,1950 EST5EDT
EST5EDT  -9223372036854775808 = NULL
EST5EDT  -9223372036854689408 = NULL
EST5EDT  Sun Mar 31 06:59:59 1918 UT = Sun Mar 31 01:59:59 1918 EST isdst=0 gmtoff=-18000
EST5EDT  Sun Mar 31 07:00:00 1918 UT = Sun Mar 31 03:00:00 1918 EDT isdst=1 gmtoff=-14400
EST5EDT  Sun Oct 27 05:59:59 1918 UT = Sun Oct 27 01:59:59 1918 EDT isdst=1 gmtoff=-14400
EST5EDT  Sun Oct 27 06:00:00 1918 UT = Sun Oct 27 01:00:00 1918 EST isdst=0 gmtoff=-18000
EST5EDT  Sun Mar 30 06:59:59 1919 UT = Sun Mar 30 01:59:59 1919 EST isdst=0 gmtoff=-18000
EST5EDT  Sun Mar 30 07:00:00 1919 UT = Sun Mar 30 03:00:00 1919 EDT isdst=1 gmtoff=-14400
EST5EDT  Sun Oct 26 05:59:59 1919 UT = Sun Oct 26 01:59:59 1919 EDT isdst=1 gmtoff=-14400
EST5EDT  Sun Oct 26 06:00:00 1919 UT = Sun Oct 26 01:00:00 1919 EST isdst=0 gmtoff=-18000
EST5EDT  Mon Feb  9 06:59:59 1942 UT = Mon Feb  9 01:59:59 1942 EST isdst=0 gmtoff=-18000
EST5EDT  Mon Feb  9 07:00:00 1942 UT = Mon Feb  9 03:00:00 1942 EWT isdst=1 gmtoff=-14400
EST5EDT  Tue Aug 14 22:59:59 1945 UT = Tue Aug 14 18:59:59 1945 EWT isdst=1 gmtoff=-14400
EST5EDT  Tue Aug 14 23:00:00 1945 UT = Tue Aug 14 19:00:00 1945 EPT isdst=1 gmtoff=-14400
EST5EDT  Sun Sep 30 05:59:59 1945 UT = Sun Sep 30 01:59:59 1945 EPT isdst=1 gmtoff=-14400
EST5EDT  Sun Sep 30 06:00:00 1945 UT = Sun Sep 30 01:00:00 1945 EST isdst=0 gmtoff=-18000
EST5EDT  9223372036854689407 = NULL
EST5EDT  9223372036854775807 = NULL

OK?  There's dump number one.  Now let's compare to dump number two:

unicorn:~$ zdump -v -c 1918,1950 America/New_York
America/New_York  -9223372036854775808 = NULL
America/New_York  -9223372036854689408 = NULL
America/New_York  Sun Mar 31 06:59:59 1918 UT = Sun Mar 31 01:59:59 1918 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar 31 07:00:00 1918 UT = Sun Mar 31 03:00:00 1918 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Oct 27 05:59:59 1918 UT = Sun Oct 27 01:59:59 1918 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Oct 27 06:00:00 1918 UT = Sun Oct 27 01:00:00 1918 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar 30 06:59:59 1919 UT = Sun Mar 30 01:59:59 1919 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar 30 07:00:00 1919 UT = Sun Mar 30 03:00:00 1919 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Oct 26 05:59:59 1919 UT = Sun Oct 26 01:59:59 1919 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Oct 26 06:00:00 1919 UT = Sun Oct 26 01:00:00 1919 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar 28 06:59:59 1920 UT = Sun Mar 28 01:59:59 1920 EST isdst=0 gmtoff=-18000
America/New_York  Sun Mar 28 07:00:00 1920 UT = Sun Mar 28 03:00:00 1920 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Oct 31 05:59:59 1920 UT = Sun Oct 31 01:59:59 1920 EDT isdst=1 gmtoff=-14400
America/New_York  Sun Oct 31 06:00:00 1920 UT = Sun Oct 31 01:00:00 1920 EST isdst=0 gmtoff=-18000
[...]

I'm truncating this one because it's much longer.  Apparently this one
shows every year, even if there are no DST rule changes that year.  What
does this mean?  Hell if I know.  Let's pick a date that's in one of
these dumps but not the other, shall we?

unicorn:~$ TZ=America/New_York date -d '1920-03-28 +4 hours'
Sun Mar 28 05:00:00 EDT 1920
unicorn:~$ TZ=EST5EDT date -d '1920-03-28 +4 hours'
Sun Mar 28 04:00:00 EST 1920

There.  There's a timestamp where you get a different result.  I'm
sure there are more.

If being wrong about times in 1920 (and probably other years as well)
is not acceptable to you, then you should switch to America/New_York.

If the idea that you would ever CARE about the clock reading at various
times during the 1920s is laughable to you, then do whatever you want,
but please don't advocate that others follow your example.

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Thread

ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 01:50 +0100
  Re: ntpsec as server questions jeremy ardley <jeremy.ardley@gmail.com> - 2023-12-04 02:00 +0100
    Re: ntpsec as server questions jeremy ardley <jeremy.ardley@gmail.com> - 2023-12-04 02:10 +0100
      Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 10:00 +0100
        Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-04 12:00 +0100
          Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 12:40 +0100
            Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-04 13:20 +0100
              Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 17:00 +0100
                Re: ntpsec as server questions Dan Purgert <dan@djph.net> - 2023-12-04 17:40 +0100
                Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 22:30 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-05 04:00 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-04 17:40 +0100
                Re: ntpsec as server questions Max Nikulin <manikulin@gmail.com> - 2023-12-04 18:10 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-04 19:50 +0100
                Re: ntpsec as server questions Max Nikulin <manikulin@gmail.com> - 2023-12-16 11:40 +0100
                Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 22:30 +0100
                Re: ntpsec as server questions John Hasler <john@sugarbit.com> - 2023-12-04 17:40 +0100
                Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 22:40 +0100
                Re: ntpsec as server questions Tom Furie <tom@furie.org.uk> - 2023-12-04 17:50 +0100
              Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-04 20:20 +0100
                Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 22:40 +0100
              Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 20:20 +0100
          Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-04 13:20 +0100
            Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-04 14:00 +0100
            Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 21:30 +0100
              Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-04 21:40 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-04 22:50 +0100
                Re: ntpsec as server questions jeremy ardley <jeremy.ardley@gmail.com> - 2023-12-05 00:50 +0100
            Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 21:30 +0100
              Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-04 23:20 +0100
                Re: ntpsec as server questions Max Nikulin <manikulin@gmail.com> - 2023-12-05 17:40 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-05 18:10 +0100
                Re: ntpsec as server questions Max Nikulin <manikulin@gmail.com> - 2023-12-06 13:30 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-06 14:10 +0100
                Re: ntpsec as server questions Max Nikulin <manikulin@gmail.com> - 2023-12-06 16:10 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-06 16:50 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-06 17:20 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-06 17:30 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-06 17:50 +0100
                Re: ntpsec as server questions Curt <curty@free.fr> - 2023-12-06 17:50 +0100
                Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-05 18:30 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-05 18:30 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-06 06:30 +0100
                Re: ntpsec as server questions Max Nikulin <manikulin@gmail.com> - 2023-12-06 17:50 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-06 18:10 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-06 18:30 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-06 18:40 +0100
                Re: ntpsec as server questions Curt <curty@free.fr> - 2023-12-06 18:50 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-06 19:00 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-06 19:10 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-06 19:30 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-06 21:50 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-07 00:20 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-07 01:20 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-07 01:30 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-07 01:30 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-07 01:40 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-07 01:50 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-07 02:50 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-07 06:50 +0100
                Re: ntpsec as server questions Max Nikulin <manikulin@gmail.com> - 2023-12-08 03:40 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-08 04:10 +0100
                Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-08 05:20 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-08 13:20 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-08 18:00 +0100
                Re: ntpsec as server questions Max Nikulin <manikulin@gmail.com> - 2023-12-09 12:20 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-08 13:40 +0100
                Re: ntpsec as server questions <tomas@tuxteam.de> - 2023-12-08 14:20 +0100
                Re: ntpsec as server questions "Thomas Schmitt" <scdbackup@gmx.net> - 2023-12-08 14:40 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-08 18:10 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-06 21:30 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-07 00:20 +0100
                Re: ntpsec as server questions <tomas@tuxteam.de> - 2023-12-07 06:40 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-07 06:50 +0100
                Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-07 13:20 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-07 14:10 +0100
                Re: ntpsec as server questions John Hasler <john@sugarbit.com> - 2023-12-07 15:30 +0100
                Re: ntpsec as server questions Pocket <pocket@columbus.rr.com> - 2023-12-07 15:40 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-07 17:00 +0100
                Local time in databases (Re: ntpsec as server questions) Max Nikulin <manikulin@gmail.com> - 2023-12-07 16:40 +0100
                Re: Local time in databases (Re: ntpsec as server questions) <tomas@tuxteam.de> - 2023-12-07 17:10 +0100
                Re: Local time in databases (Re: ntpsec as server questions) Max Nikulin <manikulin@gmail.com> - 2023-12-08 03:20 +0100
                Re: Local time in databases (Re: ntpsec as server questions) Nicholas Geovanis <nickgeovanis@gmail.com> - 2023-12-08 05:20 +0100
                Re: Local time in databases (Re: ntpsec as server questions) <tomas@tuxteam.de> - 2023-12-08 05:40 +0100
                Re: Local time in databases (Re: ntpsec as server questions) Max Nikulin <manikulin@gmail.com> - 2023-12-12 18:10 +0100
                Re: Local time in databases David Wright <deblis@lionunicorn.co.uk> - 2023-12-17 06:20 +0100
                Re: Local time in databases (Re: ntpsec as server questions) <tomas@tuxteam.de> - 2023-12-08 05:40 +0100
                Re: ntpsec as server questions James Cloos <cloos@jhcloos.com> - 2023-12-06 22:30 +0100
                Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-07 06:50 +0100
              Re: ntpsec as server questions David Wright <deblis@lionunicorn.co.uk> - 2023-12-05 04:00 +0100
      Re: ntpsec as server questions Anssi Saari <anssi.saari@debian-user.mail.kapsi.fi> - 2023-12-04 11:10 +0100
        Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 12:30 +0100
          Re: ntpsec as server questions <tomas@tuxteam.de> - 2023-12-04 12:50 +0100
  Re: ntpsec as server questions Greg Wooledge <greg@wooledge.org> - 2023-12-04 02:00 +0100
  Re: ntpsec as server questions <tomas@tuxteam.de> - 2023-12-04 06:10 +0100
    Re: ntpsec as server questions Jeffrey Walton <noloader@gmail.com> - 2023-12-04 06:30 +0100
      Re: ntpsec as server questions Charles Curley <charlescurley@charlescurley.com> - 2023-12-04 07:30 +0100
        Re: ntpsec as server questions Jeffrey Walton <noloader@gmail.com> - 2023-12-04 08:10 +0100
    Re: ntpsec as server questions gene heskett <gheskett@shentel.net> - 2023-12-04 11:00 +0100

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