No DST Patch installed but having NTP client.

[Guna_2]

Hi Folks,

I have an hpux-11.11 & Solaris boxes. I don't have 2007 DST patch installed on those boxes. As per the old DST patch, the DST change will appear on OCT-28th.

My servers have Ntp client configured and synchronizes the time from NTP server, which could have DST patch applied.

I think at OCT-28, my server may apply the DST change & it may go 1 hour back. But with the help of NTP, will it get sync to the server’s time (1hour forward)?

What else I can do to prevent this problem other than installing the patch?


Thanks & Regards,
---MGP---

[Dennis Handly]

NTP won't change anything because it only adjusts the UTC/GMT time. DST only changes the offset from GMT.

You need to install PHCO_37053 if you are dealing with any of the US or Canadian timezones.

A good question is why wasn't this patched back in March?

[skt_skt]

what is the current tztab patch you have?
PHCO_37053 is the latest in the tztab patch available

[A. Clay Stephenson]

If you stop and think about your question a moment, you will realize how naive (if I were less tactful and sensitive, I would say dumb) it actually is. A UNIX box might have many users connected from around the planet and each with his own TZ setting. DST rules might apply to some and not to others. The system only keeps up with UTC (and more accurately seconds since 1-Jan-1970 00:00:00 UTC) and it is this time that NTP adjusts. How this time is displayed is determined by a processes TZ setting and the underlying libc() date functions. It is these functions that the patch addresses through a revised /usr/lib/tztab file and the only fix is to apply the patch (or manually edit the tztab file).

[skt_skt]

The rules for DST have changed in 2007 for the first time in more than 20 years. The new changes were enacted by the Energy Policy Act of 2005, which extended the length of DST in the interest of reducing energy consumption. The new rules increase the length of DST by about one month. DST will now be in effect for 238 days, or about 65% of the year, although Congress retained the right to revert to the prior law should the change prove unpopular or if energy savings are not significant. Beginning in 2007, Daylight Saving Time in the United States

begins at 2:00 a.m. on the second Sunday of March and
ends at 2:00 a.m. on the first Sunday of November
In 2007 DST will begin on March 11th. Set your clocks ahead one hour on Sunday, March 11, 2007.

In 2007 DST will end on November 4th. Set your clocks back one hour on Sunday, November 4, 2007.


There shouldn't be any problems if your operating system has the latest updates. All NIST time services broadcast Coordinated Universal Time (UTC). Corrections for your local time zone and for Daylight Saving Time are provided by your computer's operating system. Therefore, it is important that you have the latest software updates for your operating system.

The great majority of computer time codes sent by the NIST Internet Time Service (ITS) use the Network Time Protocol (NTP), which contains no information about DST, and relies on your computer's operating system to determine whether DST or ST is in effect. Therefore, if you use NTP, it is especially important to use an operating system that has been patched to conform to the new DST rules.

see more info at

http://tf.nist.gov/general/dst.htm

[skt_skt]

11.00 PHCO_35991
PHCO_35991 supersedes PHCO_34673 and PHCO_34266
PHCO_34266 is the minimum patch level required to support the 2007 U.S. DST changes for U.S. systems
11i v1 PHCO_35989
PHCO_35989 supersedes PHCO_34668 and PHCO_34342
PHCO_34342 is the minimum patch level required to support the 2007 U.S. DST changes for U.S. systems
11i v2 PHCO_35990
PHCO_35990 supersedes PHCO_34669 and PHCO_34375
PHCO_34375 is the minimum patch level required to support the 2007 U.S. DST changes for U.S. systems
11i v3 PHCO_35992
HP-UX 11i v3 will support the 2007 U.S. DST changes for U.S. systems at the time of release. PHCO_35992 is the minimum patch level required to support the 2007 U.S. DST changes for systems in Mexico & Canada