NTP and summer time

Answered Question
Apr 20th, 2007
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I was reading up on NTP, and I've come across this:


"Some areas, such as most of North America and Europe, have consistent and common rules for when to switch between winter or Standard time and summer or Daylight Saving Time. The traditional North American rule, and the default for Cisco routers when they are configured for summer time, is to move an hour ahead at 2:00 AM on the first Sunday in April, and back an hour at 2:00 AM on the last Sunday in October."


As here in Europe the summer time begins the last week of March and ends last Weekend of October, I was wondering:

Is it enough to point the device to an NTP server specifying on this the right time zone, or do I also have to manally set the summertime period e.g.:

Router(config)#clock summer-time BST recurring last sun mar 01:00 last sun oct 01:00


Thanks to read

Correct Answer by Wilson Samuel about 10 years 3 months ago

Hi,


NTP is always used as a reference clock and not as a local clock, as the NTP server just points the 'correct time' and we need to specify our 'local time' and DST settings, so that even in the case of a router reboot or link failure the router can cross check its own time with a reference clock and adjust the local time accordingly.


Regards,

Wilson Samuel

HTH


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Craig Balfour Fri, 04/20/2007 - 06:59
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NTP servers only work with time in Coordinated Universal Time (UTC).


Devices use their configured timezone settings to convert this UTC value into localtime.


The NTP server likewise has no knowledge of daylight saving time. Your device would need to be configured with this setting in order to make the correct adjustment to localtime when the change-over occurs.


Correct Answer
Wilson Samuel Fri, 04/20/2007 - 10:28
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    Mobile User, July 2015

Hi,


NTP is always used as a reference clock and not as a local clock, as the NTP server just points the 'correct time' and we need to specify our 'local time' and DST settings, so that even in the case of a router reboot or link failure the router can cross check its own time with a reference clock and adjust the local time accordingly.


Regards,

Wilson Samuel

HTH


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