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Questions tagged [ntp]

NTP stands for Network Time Protocol, and it is an Internet protocol used to synchronize the clocks of computers to some time reference.

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Better to use same or closer NTP servers when distributed?

I have a group of servers located in several data centers. They should all be synced so that they have the same time, and ideally, should also have the correct time. Is it better to sync them all with the same servers, irrespective of geography, or…
squidpickles
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How does one make sure or even guarantee server time are sync correctly between dozens of servers across multiple datacenter on different location?

Currently our web applications contain a logic to check if the data sent to the web server is expired or not by comparing the timestamp of the data with the date/time of the server. Everything goes will, until some dude from data center accidentally…
forestclown
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Delay NTP Initialisation, Cisco 877W, IOS 12.4(24)T1

I have a Cisco 877W which I'm using for my home ADSL connection (and as a refresher in Cisco IOS). I've got a working config in-place with my PPPoA connection coming online correctly, and VLANs and other settings configured as I want them, but I…
Mike Insch
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Nagios NTP, discarding peer

We're using nagios check_ntp_time for monitoring time on our servers. Unfortunately the service is flapping. And reporting a lot of false-positives. It happens everytime for random server in random day time and lasts for ~10-30 minutes. When the…
Michal Bryxí
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Synchronizing time with only one NTP server

I have a linux machine on a network where the machine only has access to exactly one NTP server. After the time synchronization the status looks like this: [root@test ~]# ntpq -p remote refid st t when poll reach delay offset…
Zizzencs
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ntpd crashes without removing pid file

We occasionally have seen time differences on our servers, and confirmed that: ntpd crashed without any traceable logs ntpq process was dead, but pid existed at /var/run/ntpd.pid /etc/init.d/ntp restart then ntpq -p, problem solved At first, ntpq…
kenn
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Fake SNTP server for testing

I want to setup an SNTP server for testing purposes that can be set to any arbitrary value (for example testing DST behaviour of the device under test) serve only on eth1 on my RedHat Enterprise box. I want to limit it into a single interface (or…
Atilla Filiz
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Lost NTP sync on SQL servers

I've just noticed that one of our clients SQL servers are syncing against time.microsoft.com, the rest of the domain is looking at ntp.[clients.domain].co.uk, so our SQL servers are about 3 minutes fast. My argument is that we need to stop all SQL…
Patrick
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periodically overridding NTP for simulation purposes

I have this situation: NTP is used to sync time on a set of Windows 7 and Server 2008 machines. Nothing out of the ordinary about this. periodically on this system, the time needs to be changed for testing/training purposes (it is a training…
Gerard
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Configure Snow Leopard Server as NTP server for private LAN with no Internet access

I have a Snow Leopard Server box running on a private LAN with no Internet access. If you can avoid ever doing this, you should, as not having an Internet connection has brought us hours and hours of headaches. Anyway, our most recent headache is…
Justin Force
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what is the easiest way to test the impact of NTP step changes on other software?

During testing of our configuration of Red Hat Cluster System, NTP stepped the time by 16 seconds, and soon afterwards the cluster software locked up. ntpd[30917]: time reset -16.332117 s I need to repeat the failure to ensure that it was not just a…
Martin
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Compare two NTP servers

I want to compare the time used by our internal servers against time.microsoft.com. Is there an easy way to do this? Basically a third party sends me messages stamped with a time that has been synced iwth time.microsoft.com, unfortunately our…
David Turner
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Accurate DateTime synchronization for Workstations?

How do I synchronize and ensure that the workstations have accurate DateTime synchronized when needed? We have to change workstation date-time for testing some apps. How do I ensure back original date-time with accuracy? I've heard there are some…
s_ruchit
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Chronyc equivalent for ntpdate -q

According to ntpdate and chronyd man pages In ntpdate -q : Query only - don't set the clock. chronyd -q : When run in this mode, chronyd will set the system clock once and exit. It will not detach from the terminal. Is there any alternative…
Dexpras
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The "least bad" settings for Chrony as the NTP server on a virtual machine

I'm tasked with rebuilding a LAN server that's serving as the NTP server for hundreds of client machines. Unfortunately, it's on a virtual machine, and as demonstrated by questions like What are the limits of running NTP servers in virtual machines?…
JK Laiho
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