Tagged Questions

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
40 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 ...
0
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0answers
77 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 ...
0
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0answers
8 views

Why does (should?) dispersion prevent ntp from updating?

Yes, root dispersion is the maximum clock time difference that was ever observed between the local clock and the root clock. I'm still not sure what this means exactly. The situation that develops is ...
5
votes
2answers
145 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
votes
1answer
64 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
45 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", ...
-1
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1answer
46 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
51 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 ...
0
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0answers
31 views

Time Sync Issue for vm PDC on HyperV

I am a bit new the this forum. Not sure where to start but I basically found an article on this forum about HyperV Time Sync for VM Domain Controller. The owner of the post described the problems that ...
0
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0answers
33 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
61 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 ...
1
vote
1answer
72 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
votes
1answer
54 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 ...
-1
votes
1answer
35 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
votes
2answers
53 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
votes
3answers
230 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 ...
0
votes
1answer
627 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 ...
0
votes
1answer
130 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
votes
3answers
261 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 ...
0
votes
1answer
45 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 ...
0
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0answers
66 views

Signed NTP authentication

Using ansible, I have setup several Signed NTP servers around our network. The servers themselves are Virtual Hosts running on CentOS 6.5. I have the virtual machine guests on each host contact their ...
4
votes
1answer
384 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 ...
1
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1answer
58 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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votes
2answers
121 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
104 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 ...
3
votes
1answer
259 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 ...
0
votes
1answer
791 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
votes
1answer
140 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
556 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
533 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
votes
2answers
203 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
votes
2answers
210 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 ...
1
vote
0answers
453 views

ntp is not syncing on centos server but gets response from remote server

I have googled for days before asking and I feel like I have tried everything but ntp is still not updating the time of the system automatically. I have left it running for days and still I get the ...
1
vote
1answer
162 views

Domain member as ntp server for other (non-domain) network

I am attempting to synchronize the date and time for a number of computers belonging to a non-domain, statically configured network (e.g. computer B in illustration) with a node which is residing in a ...
0
votes
1answer
88 views

Set a system's time server to itself

I work on a standalone network that has 3 domain controllers all running Server 2008 r2. Two of the servers are physical (DC1 / DC2) and one is virtual (DC3). I want all my systems to refer to DC1 as ...
0
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0answers
38 views

How can I select ntp the time source for a system?

I have two Windows 2008 servers running Meinburg NTP. When I run ntpq.exe -p from one, I see that there are sources specified as current, selected, or discarded (via a +, -, or *). On another system, ...
0
votes
2answers
558 views

Both my ntp servers are marked as falsetickers in the status [closed]

I have a linux box, set up with two ntp servers to sync. This box in case, was extremely out of sync (61 seconds) before it was forced sync. The following outputs are 1 hour after this sync. When ...
2
votes
0answers
76 views

System clock jumps over 50 seconds randomly

Having a really strange and frustrating issue with system clocks across a few (non virtualized) Ubuntu 12.04 servers. The system clock jumps unpredictably by over 50 seconds. Here's a part of the ...
1
vote
2answers
56 views

IP auto changed on Win2k8 VM

I'm having a problem with my Win2k8 virtual machine. After the virtual machine boot, it gets an IP address from DHCP. But later on, NTP makes a big time shift, so Windows automatically renew (in fact ...
0
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2answers
262 views

Set NTP not to receive time from peers on Ubuntu

In my /etc/ntp.conf, it says By default, exchange time with everybody, but don't allow configuration. restrict -4 default kod notrap nomodify nopeer noquery restrict -6 default kod notrap nomodify ...
1
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0answers
136 views

ntpd -gq do not working on CentOS 6.4

when I'm running 'ntpd -gq' from CentOS 5.10 (i686) the time is synced, but in CentOS 6.4 (x86_64) the command gets stuck (I need to stop it using ctl+c). Any idea hoe to fix it? EDIT: iptables ...
1
vote
0answers
131 views

ntpd default rate limiting?

I've got about 70 linux instances running on an OpenStack cluster that currently consists of two compute nodes and one controller. Also, these machines live in a RackSpace DC as part of their 'Private ...
0
votes
1answer
122 views

Easiest Way to Keep Time Synced on VMware Cluster

I have a three host VMware cluster (5.1) running mainly windows 2008r2 servers with a single DC. I'm having allot of problems with time drift across the servers and while I've found several articles ...
3
votes
1answer
120 views

Synchronizing RODCs to NTP servers?

I've read this nice article from Gareth Hooper regarding Domain Controller syncing to external time sources. In essence, he wrote that although Microsoft don't actually condone the practice, it's a ...
4
votes
2answers
3k views

Active Directory Time Synchronisation - Time-Service Event ID 50

I have an Active Directory domain with two DCs. The first DC in the forest/domain is Server 2012, the second is 2008 R2. The first DC holds the PDC Emulator role. I sporadically receive a warning ...
2
votes
2answers
140 views

Why does ntpd need to bind external interfaces to sync the local clock?

I wanted to tighten my security so I don't want to open any ports that are not really needed. I have no intentions of running an ntp server for other people to use, I only run the ntp daemon to keep ...
2
votes
0answers
180 views

Server 2008 will not sync with NTP [closed]

I recently got given a server 2008 r1 machine and thought I would set it up to help maintain my small work network of 10 PCs better. The issue I am having is that I cannot get it to sync with an ...
2
votes
2answers
161 views

How to configure NTP has a TAI or GPS time reference?

For our project, we would like to have all servers and systems synchronised to a linear time reference (without leap second). Therefore, we would discard UTC but are very interested in advertising ...
3
votes
1answer
160 views

The wisdom of 'server 127.127.1.0' in ntp.conf for virtual servers

Considering the 'undisciplined local clock' on VMs is not what you'd call accurate in most cases, how wise is it to include lines such as these in your NTP configuration? # Undisciplined Local Clock. ...
2
votes
3answers
5k views

Why should I need a tweak to force VMware ESXi 5 to sync time with Windows NTP server

I'm plagued by a seemingly simple but actually troublesome problem, so I ask for help here. Symptom I installed an instance of VMware ESXi 5.1 inside VMware Workstation to learn about various ESXi ...