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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1answer
210 views

date and sleep during leap second [closed]

Did you ever watch what happens with a sleep during a leap second or what date will show us? Most UNIX systems can handle a sleep with a fraction of a second and the date command can display ...
2
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1answer
189 views

NTP offset warning when no NTP server is defined and NTP not running?

I just want to preface by saying that I am still learning linux and don't have too much experience with it. My job requires me to monitor an alert system for our clients hosts that are running our ...
1
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0answers
947 views

Cisco SG300 SNTP servers always down

I'm trying to setup the SNTP of a new Cisco SG300-48 Switch in L3 mode. So far I have enabled the Main Clock Source (SNTP Servers) option (Administration -> Time Settings), set my time zone and ...
6
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2answers
807 views

What happens when DC cannot reach external time server?

We have a small Windows 2012 R2 domain with a single DC. The DC is advertising as a time server, and the clients are syncing just fine. The DC is getting its time from an external time server, and ...
1
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0answers
306 views

Why my server on Digital Ocean woke up with a wrong time?

Today one of my servers hosted on Digital Ocean (the only one hosted there) is reporting wrong time. It's two hours late. sudo dpkg-reconfigure tzdata # then I set up the timezone to Europe/Rome ...
0
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136 views

Using RTC to synchronize ntpd when offline

I need a stable configuration, presumably using ntpd, to keep system clock as precise as possible. Background: I have several embedded devices (arm9) running linux (currently: 3.16.1 / debian 7.2) ...
1
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0answers
60 views

Server Migration 03 -> 12

I have run into a wall and out of ideas. Here's the situation. I have a client that has a old '03 DC with a 12 replicating the '03 server. It is out dated and has to many group policies and stuff it ...
1
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1answer
367 views

Resync windows time after a long power outage

I'm facing the following situation: We have a computer with Windows 8 Standard Embedded. The machine is an industrial computer that doesn't have a CMOS Battery but a capacitor (a Gold Cap acting as a ...
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0answers
75 views

Ubuntu server is randomly having large time sync issues

It seems that randomly the time on my server will jump forward several hours. This happens randomly and the only way I've found to fix it is to manually force an NTP call. I don't see anything out of ...
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2answers
62 views

What does this shell script mean? [closed]

#!/bin/bash /usr/sbin/ntpdate ntp.jst.mfeed.ad.jp I found such a script file,maybe it is used to confirm the time, can you explain it in detail?
4
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1answer
213 views

ntpd keeps adding local servers while being told not to

I'm configuring ntp inside a corporate network. I've done restrict default ignore restrict -6 default ignore and listed servers explicitly (I'm using public servers from pool.ntp.org). I also ...
3
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2answers
150 views

ntp authentication - MD5 - freeBSD

NTP claims to support md5 authentication. The docs I've found aren't clear enough for my level of luserhood. How would I go about using it, with a collection of freebsd clients, and a couple of ...
3
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2answers
1k views

How to have ntpd serve only my local subnet

I have a few servers with public Internet IP addresses like A.B.C.x. One of my hosts (A.B.C.10) runs ntpd and I have it syncing it's time from europe.pool.ntp.org. Now I only want to allow hosts ...
8
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2answers
426 views

Proper NTP configuration for a few servers

I have about 20 Linux servers in a small network and I need their clocks decently close to each other (e.g. within 20msec). I've started with every one of them synced to europe.pool.ntp.org and the ...
2
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1answer
987 views

NTP Version Check

How can I check other NTP server's NTP version without query the server? NTPv3 and NTPv4 network packet is different, and I know I can just catch the packet and analysis it when ntpd is doing sync. ...
0
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1answer
721 views

NTP not sync the time continuously, Have to restart the service of NTP then it SYNC in Ubuntu

I am facing one problem. NTP server not sync the time automatically. If I change the the time of system then NTP server not able to correct it. After reboot the service of NTP it sync the time ...
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1answer
171 views

How to update NTP-deamon on a Debian Squeeze (Proxmox 2.x)?

Because of security issue in NTP (CVE-2014-9295) I need to update NTP-deamon on a Debian Squeeze (it is the Proxmox 2.x installation). The problem is that it is a productional system and I can not ...
5
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2answers
7k views

Windows Server 2012 time keeps setting itself 12 minutes ahead

Our Active Directory server has a problem whereby the time keeps setting itself 12 minutes ahead of the real time. This causes authentication issues on the network. I have tried syncing to an ...
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2answers
54 views

Does windows server provide a standards-based NTP service?

We use a PHP script for syncing time against a NTP time server. All of it works, but when working with windows server, the script fails. Is there a modified version of NTP working inside the original ...
1
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1answer
189 views

Main DC is no longer NTP or hold FSMOs

Good Afternoon, We two virtual DC and one local physical read only DC. When we moved our data center offsite with a warm backup site we p to v our DC’s and DC1 was the master schema. While ...
0
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1answer
33 views

How to accommodate two sets of NTP servers

I have a case where, within one company, half of the devices synchronize to a set of NTP servers (including a GPS based one), and the other one on another set (also including stratum 1 servers). I ...
1
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1answer
51 views

Neglected services on old DC - how to move to new DC?

We have installed a new Server 2012. The new server: DC3 (192.168.0.3), has been promoted, and is now our main DC (includes : DNS, DHCP) Schema master DC3.domain Domain naming master ...
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0answers
349 views

Server times off by over 1 minute after recently syncing

I manually synced the times (and matched hardware times) on two servers A and B. NTP was running on both machines, so I made sure the /etc/ntp.conf files were identical (the time servers on B were ...
6
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2answers
3k views

Synchronize clock with NTP while online, and with RTC while offline?

Is there a existing mechanism that synchronizes a linux system with NTP while online, and with a predictably drifting RTC while offline? We operate remote "collectors": embedded Linux systems that ...
2
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1answer
907 views

configuration to use gps time with no internet connection

I use ntp with a GPS device with PPS on port /dev/ttyS0. All seems to be fine if the machine is connected to the internet. Output looks correct. But if there is no internet connection I get: $ ntpq -...
2
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1answer
528 views

udev rule running setserial low_latency don't work

My server runs Ubuntu 14.04.1. I created udev rules in /etc/udev/rules.d/09-pps.rules to get GPS with PPS support work. KERNEL=="ttyS0", SYMLINK+="gps0", MODE="0666" KERNEL=="ttyS0", RUN+="/bin/...
1
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1answer
266 views

NTP offset between PDCe and DC (Both Hyper-V)

I'm facing an issue, here is the context: 1 PDCe (192.168.1.3 and Hyper-V virtualized) is set as NTP server, its source for time is VM IC Time Synchronization. 1 DC (Hyper-V virtualized) is ...
1
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1answer
1k views

Windows Server NTP Authenication

I have setup an NTP Server on a Windows Server 2008. The Time synchronization works with Windows Clients and Non Domain Clients but now i have switches that want to authenticate against NTP Server and ...
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0answers
344 views

RedHat ntp offset becomes bigger over time

I have a strange issue with a server. It is configured to use 2 servers, just like all the other server (the config is the same for a couple of server and they are all working except this one) and it ...
1
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1answer
212 views

How should I manage and troubleshoot NTP issues?

For some time now I've been fighting with some NTP issues in my company's network and I'm having a hard time to understand how the commands combine with the service. For example: In the server's /etc/...
1
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1answer
535 views

How can I have ntpdate ignore skew?

During a server bootstrap process, I want to explicitly run ntpdate rather than rely on the ntp daemon. However, the clock can be severely skewed at this point in time, which causes an error when ...
0
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1answer
141 views

How can I test that I am correctly setting a new ntp server?

I have a config script that is configuring the ntp server of a machine (which is running Ubuntu 14.04) by stripping lines matching ^server .* from /etc/ntp.conf and adding a new line server new.ntp....
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1answer
81 views

ntp daemon seems useless and why my server date time is far behind my local time

I've installed ntp daemon in ubuntu to sync my date time with the network time. Now my time on the server is 11:00 while my PC date/time is 19:30. Now all my transactions date/times are logged ...
0
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2answers
282 views

SES time sync error

My SES setup was running fine for the last 6 months without any issues. All of a sudden it stopped working yesterday and I'm gettinng the infamous time sync error. Naturally I assumed ntpd had ...
3
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3answers
3k views

How to keep the time on multiple servers in sync

I want a cluster of servers to have the exact same time. All are using UTC time zone. Using NTP currently, i still see they seem to be off by 10-20 miliseconds each. Whats the best way to have them ...
3
votes
1answer
9k views

Nagios - check_ntp_time - Offset Unknown

I have a local NTP server running on the subnet to keep other subnet nodes in sync, without every node syncing with upstream servers. But, while implementing the check_ntp_time plugin for Nagios I am ...
1
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1answer
659 views

Windows Server system time drifts badly on Amazon EC2 instance

We've been using an EC2 micro instance for a little remote monitoring for the past few weeks, and it's bothered me badly how the system time is never accurate; no matter how much fighting I did with ...
2
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3answers
14k views

Why doesn't the time match on two Windows Domain Controllers despite resync?

In my domain there are two domain controllers, there is a gap of 3 minutes between their times and than I can find this difference between many clients (it depends on their DC). If I run this command:...
0
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1answer
104 views

Virtual guest: NTP sync with host

Is there any way to get a virtual guest to only query it's current host for NTP? I'm not talking about configuring ntp.conf with the host's IP here either as VLAN's & firewalls may block that ...
5
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1answer
6k views

Why is the time on my Server 2008 R2 DC wrong? It's syncing to ntp.org, it claims

OK. After a lot of fun with syncing time across my workstations, I got that sorted out. My workstations are now perfectly synced with my Server 2008 R2 Domain Controller (physical server, not virtual)....
1
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2answers
165 views

NTP Server in Network Switch

Is it possible to set up a Switch to acts an NTP Server for the devices connected to its VLAN ? If so ,how can I implement it my HP Switch A3600 JG299A. I want to do this because I do not have ...
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2answers
585 views

NTP is not updating the time in local machine [closed]

We are having the server in AWS with Amazon linux. By Default it comes with NTP service and we can see the sync. However when someone change the clock or timing using the below command.... date -s "...
0
votes
1answer
292 views

Group Policy for Time Sync = ARP Flood?

I have a Windows Server 2008 R2 domain controller and a bunch of workstations of various versions of Windows - XP SP3, Vista, 7, 8.1. Time sync wasn't working correctly on a few PCs so I followed the ...
4
votes
1answer
3k views

Windows NTP Server A Stratum is 2, Windows NTP Server B Stratum is 15

We have a network that is mostly separated from our corporate network. The corporate network uses ntp1.corpaddress.tdl. We have a second server, isolated.corpaddress.tdl. It is getting its NTP time ...
1
vote
1answer
6k views

How to configure a Cisco Catalyst 2960 to synchronize with an NTP server

I would like to synchronize a Cisco Catalyst 2960 series switch with a publicly available NTP server such as time.apple.com. I have reviewed the knowledge base article here: Catalyst 2960 ...
0
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1answer
392 views

Windows server and AWS clock synchronization

I have a Windows 7 computer that communicates with Amazon Web Servers (S3, SES). This server uses windows internet time for clock synchronization time.windows.com. On my linux machines I ran into ...
3
votes
1answer
3k views

Windows NTP server with Linux clients

Has anyone got any experience syncing Linux (specifically Red Hat) to a Windows NTP server? Currently our Windows server is syncing to an stratum 1 server on the internet but the Linux boxes refuse to ...
13
votes
2answers
670 views

What can be done to improve time synchronization on networks with sporadic internet access?

I'm looking for advice setting up time servers for a very non-typical network. I support many closed networks that have occasional access to the internet. A network would get access most days for a ...
0
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2answers
751 views

Troubleshooting unwanted NTP Traffic

A domain controller running Windows Server 2012 is sending NTP and NETBIOS traffic to an address that has never been configured as a time provider. The server logs give no indication that any NTP ...
2
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2answers
1k views

High Jitter in NTP and poll value never goes above 128

I have a lot of servers syncing to the same NTP servers (4). Not every server is in the same LAN. Some are 3 hops away from the NTP servers and some are 6 hops away. On couple of servers I see that ...