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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Yosemite 10.10.5 Clock drifts while asleep

We have a cart of Macbook Pros with Yosemite 10.10.5 installed on them. Our school network uses 802.1x for authentication to the WiFi, but when these laptops are put in their carts and left to sit ...
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Is it possible for NTP to have two system peers at the same time?

In some rare cases, ntpq -p reports here that it has two system peers, like this (IPs and results anonymized): remote refid st t when poll reach delay offset disp ==========...
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153 views

Windows server time keeps setting the time 2 hours back

Our Windows 2012 server keeps setting its system clock 2 hours back. I've tried to run 'w32tm /resync' a couple of times but that does only works on short term. the server manager gives an Error ...
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363 views

How to fix time on NTP server with a lot of machines synchronized by it

I have one NTP server which has a wrong time setting which are 7 hours in the future (timezone was changed after machine shipment, but not the time). The server itself is not synchronized, but only ...
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219 views

AWS - ELB - NTP - Unable to forward UDP Traffic?

I am trying to setup two micro-instances behind an internal ELB which will handle mundane tasks such as central logging and NTP queries, but come to realize that ELB doesn't support UDP forwarding. ...
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81 views

Configuring Windows Times Service for non-PDC emulator

Not to get to deep into the weeds, here's the gist. A SysAdmin of ours created GPOs on the Domain Controllers Policy (DCP) and we've been having time issues ever since. Neither he nor I know if the ...
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88 views

Is it possible to increase the rate at which ntpd updates the system clock?

We have some hosts that have gotten out of sync due to ntpd being mis-configured, with an ntp server that was unreachable. Our clocks on some hosts (CentOS 6) are now upwards of 30 seconds off (in the ...
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How do I query a Domain Controlers NTP service from a linux box?

I need to confirm that a Domain Controller is acting as a NTP time server for non windows devices and servers. I figure there must be a command in linux that will query an NTP server and see if it is ...
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37 views

Securing my NTP configuration

Need some assistance configuring my ntp.conf file for my primary NTP server. Does my configuration accomplish the following: Prevent the servers being polled from changing my configuration? Allow ...
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95 views

ntpdate on ec2: no server suitable for sychronization

I'm trying to turn NTP on for a handful of EC2 instances inside a VPC, starting with ntpdate, since my server is pretty far off and I don't want it to slew. I'm running into the 'no server suitable ...
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841 views

Windows 2012 R2 NTP server Unable to sync with Cisco Nexus

I am the PDC Admin, The Windows NTP server is set correctly, we have 5 different time sources set. We are able to sync with 2 of those time sources and other external time sources such as ntp.org (...
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121 views

How accurate can we get computer clocks synchronized in a local network of any number of computers?

In the past, I have seen that most of my computer on my local network don't really have the same time within up to 1 second or so. So I wanted to make sure that it would be possible for a stack of ...
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47 views

Why is the NTP local fudge server no longer reachable?

For many years I have had: server 127.127.1.0 # local clock fudge 127.127.1.0 stratum 10 In my /etc/ntp.conf configs - it always worked as I expected it to: ie. was mostly useless but for those ...
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587 views

NTP: Should I configure NTP step-tickers in a domain which uses local NTP servers?

I've bumped into something which is called "NTP step tickers" and read about it in this article, but I'm not sure if it's required in a domain which includes local NTP servers. It seems like it ...
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552 views

Best choice for NTP client configuration

Lets see if someone can throw a bit of light on this subject.. I'm making a server installation in the next days. My client wants to deploy a Hortonworks HDP with 2 servers as master servers and 5 ...
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210 views

Nagios' check_ntp_time sporadic socket timeout

Check_ntp_time has been failing on all my hosts sporadically. I usually receive CRITICAL - Socket timeout after 10 seconds And a couple of minutes later check_ntp_time succeeds and shows the ...
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69 views

NTP and iptables for time syncing within and across datacenter locations

I have several linux (Debian) servers across two data centers located on the east and west coast of the US. I picked one server from each location to be a NTP server. The NTP server syncs time with ...
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240 views

Likely causes of NTPD dying unexpectedly and solutions

On a web application which uses s3 for physical document storage, we are experiencing issues with NTP continuously dying. This seems to happen roughly once or twice a day. There is very little ...
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crypto_setup: host key file not found or corrupt

I need to deploy a ntp server with key authentication. I have Ubuntu 14.04.2 server x86_64 as ntp server and CentOS 6.7 x86_64 as client for test. For setup my ntp server I used this guide. But I ...
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149 views

Error: Failed to apply catalog: Parameter name failed on Package[ntp]:

I am getting the following error while running puppet: Error: Failed to apply catalog: Parameter name failed on Package[ntp]: Name must be a String not Array at /etc/puppet/modules/ntp/manifests/...
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108 views

Building NTP with OpenSSL

I am trying to build the latest version of NTP (4.2.8p3 released on 2015/06/29) with OpenSSL support. I can definitely build NTP but when I try to use ntp-keygen to create a new certificate it tells ...
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Trouble with NTP Sync between ntp servers and VMs

I have many VMs on production that run vmware, with vmtools running and the sync between ESXI and hosts is disabled. I run ntp client on all hosts, the OS of hosts is RHEL. The problem I have is that ...
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/proc/stat btime value change after boot

In a Linux server with the kernel 3.16, not virtualized, but with the ntp daemon active, the variable "btime" wich gives the time at which the system booted, change a few seconds before booting. For ...
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202 views

Dynamic timezone change for OpenWrt (Chaos Calmer), NTP

I have this idea for my routers running OpenWrt, since for them there is no way of knowing in what time zone they are by default. What if there was a list of lets say three time servers each per one ...
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537 views

How to solve XenServer Windows guest time driffting issue?

I do have two different Windows VM guests that seem to be drifting time seriously, reaching an offset of 10-15 seconds in less than a week. Both the Windows guests and the XenServer 6.5 host are ...
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48 views

NTP server acting weird

I have an NTP server on the network that is acting very weird. I have not changed any of the ntpd.conf settings. Its a debian box and I did a regular install. I have an NTP client on the network. If ...
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503 views

NTP service stopped in centos7.1 linux machine

In our 3 linux boxes centos 7.1, we saw below messages in the logs and then ntpd service got stopped since the offset is more than 1000s. systemd: Time has been changed ntpd[2626]: 0.0.0.0 0617 07 ...
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114 views

Windows Server internet time server reset after restart

I encountered an issue with Windows Server 2012 (running as a virtual machine), after an unplanned restart: the original internet time server - time-b.nist.gov - changed to time.windows.com. This set ...
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513 views

ntp.conf pool vs server directives

I came across an ntp.conf file that specifies pool directives: # Use servers from the NTP Pool Project. Approved by Ubuntu Technical Board # on 2011-02-08 (LP: #104525). See http://www.pool.ntp.org/...
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187 views

Linux ntpd leap second preparation

There will be a leap second on June 30, 2015 at 23:59:60 UTC. I have a Linux based stratum 1 NTP server which uses GPS as a reference clock. The server is using the "default" ntp.org ntpd. How ...
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376 views

Time synchronization in an heterogeneous environment

In a mixed environment, where machines can be running under Windows (most), Linux (a few), sometimes Android ... what is the best solution to have time synchronization with an accuracy close to ...
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35 views

UDel ntpd - completely disable time server discovery

I configured UDel ntpd (version 4.2.6.p5) as a client to three servers operated by my organization, and (I thought) no one else. server xx.yy.zz.1 iburst server xx.yy.zz.2 iburst server xx.yy.zz.3 ...
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188 views

How to synchronize the time in Debian6 server? We have 30 min delay in our VMs

I can't have the correct time in our servers. We get always the same delay in the three of them (they are VM on the same server). We use ntp to have our date always synchronized· The main server ...
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145 views

Using public ntp servers for backup to local stratum 1 server

In my data centers, I have access to a stratum 1 server but I set up our servers to use ntp pool servers in addition to it. My main thinking was for backup in case our local server goes down but I am ...
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42 views

ntp synchronize time between peers

I am a newbie, so please bear with me. I have a network of around 10 computers for which I want to synchronize their time up to millisecond precision. The computers do not have Internet connection. ...
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4k views

ntpd: servers stuck on .INIT

I am trying to set up an NTP server for my local network, but ntpd refuses to sync with outer servers. # ntptrace localhost: stratum 16, offset 0.000000, synch distance 0.396285 # ntpq -pn ...
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NTP running, server time is wrong on VM

The server time was 7 hours off (instead of 10AM it was 3AM, even though date showed the correct timezone). The output for ntpq was: $ ntpq -p remote refid st t when poll reach ...
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2k views

Does NT5DS time synchronization have any place in a mixed Windows / Linux environment?

I am working on a plan towards overhauling how time synchronization is handled on our network. Currently our network is predominantly Windows-based, in a fairly standard AD domain broken up into ...
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231 views

Tracing chain of NTP servers

For educational purposes I wanted to trace a chain of NTP servers, e.g. 0.de.pool.ntp.org back to a stratum 1 NTP server. How can I do this? I found ntptrace, but it doesn't work: /home/xyzdragon# ...
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Linux-NTP: What could cause high offset in some servers while all of them reside on the same network sigment and are configured the same?

I've installed a new NTP server and configured all Hadoop clients to use it. I've been told by the Hadoop Engineers that an offset of maximum 3 seconds is mandatory for the cluster to work properly. ...
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534 views

DST Morocco, a way to trick NTP server

From several years Morocco have been using GMT without DST, in the past years, our government reactivated the use of DST. In the first years, the DST was a mess, different periods, starts, ends, so ...
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140 views

NTP can't synchronise

Okay so I tried syncing a windows clients clock to the ubuntu ntp server i just set up, but it gets a time out, when trying. So I went on the ubuntu server and looked at syslog: Apr 10 13:15:01 ...
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499 views

Best practices for time syncing a WS2012R2 domain controller that is a Hyper-V virtual machine?

What are generally the best practices for keeping time in a WS2012R2 domain controller? Right now I have left it as installation and honestly, there is no problem ("If it aint broke, don't fix it") ...
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473 views

Time Zone keeps changing after sync with PDC in different site

Background: I have a single domain, running in 2 sites that is connected using Site-to-Site VPN. Site A is running in time zone 2:00+ UTC Site B is running in time zone 4:00+ UTC DCs are correctly ...
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160 views

how to get a subset of NTP servers from *.pool.ntp.org?

I am doing some reliability tests and needed a list of NTP servers from fr.pool.ntp.org (or any other geographic or national pool). I queried the pool 100 times but only got 13 unique servers (out of ...
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Where do computers/servers in a Windows Domain get their time settings from? [duplicate]

I have 5 Windows Server 2012 servers and around 100 computers in our domain. Recently I noticed that the time on the servers and computers is around 30 seconds fast. Where do servers and computers ...
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701 views

“NTP socket is in use” messages from ntpdate in syslog

In cron.log I can see that ntpdate is being triggered from a cron job which is running daily at 23:15 Mar 10 23:15:01 seitan /USR/SBIN/CRON[22407]: (root) CMD (/etc/network/if-up.d/ntpdate) But ...
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480 views

Can I configure a server to use a user port(>1023) for NTP?

Can a linux server be configured to use a high source port(above 1023) for NTP synchronization with a Stratum 1/2 server? Are there any disadvantages to doing this?
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Risk of starting NTP on database server?

I've heard rumors of bad things happening to database and mail servers if you change the system time while they are running. However, I'm having a hard time finding any concrete information on actual ...
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945 views

ntpd logging debug to ntpd.log

using ntpd 4.2.6p5 on redhat 6.5 How do I configure /etc/ntp.conf to generate debug messages to logfile? in /etc/ntp.conf I have logfile /var/log/ntpd.log but that only does very basic entries. ...