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

learn more… | top users | synonyms

0
votes
2answers
11 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 ...
5
votes
5answers
9k views

ntpdate -d Server dropped Strata too high

I cannot sync with a NTP source thats coming from an internal router/firewall. Anyone help ? ntppdate -d 192.168.92.82 6 Jun 11:57:30 ntpdate[5011]: ntpdate 4.1.2@1.892 Tue Feb 24 06:32:26 EST ...
4
votes
2answers
2k views

Is it viable to use w32tm /stripchart to judge time variance of two Windows hosts from each other? A better way to discover two host's time variance?

Is it viable to use w32tm.exe's option stripchart to judge the time variance of two hosts (within a very small margin of error)? Note that w32tm.exe's stripchart function is separate than the ...
0
votes
0answers
48 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
0answers
21 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 ...
2
votes
3answers
65 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
24 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
287 views

CentOS VM, NTP synchronization problems

We have three CentOS 5.9 VMs on an ESX3.5 host. Because of the nature of the services we provide it is required that the NTP time is synchronized and the time is correct on all three of them. ...
9
votes
3answers
2k views

Do I need to run a NTP server in every VM?

Couldn't the guests somehow inherit the system time of the host ? It seems kind of pointless to run the same daemon to get the same results on the same machine multiple times but I didn't find ...
0
votes
1answer
28 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 ...
2
votes
1answer
283 views

Real-time clock is wrong (from hours to years), one-time non-monotonic change at boot needed. Can Chrony solve this?

I can't guarantee a sane real-time clock on some machines (the time might be wrong by hours, months or even years). Since I also have intermittent networking, I set up Chrony in the hopes it could fix ...
0
votes
1answer
725 views

Meinberg ntp for Windows - force more frequent updates?

I have a Windows VM that has time drift problems, and left to its own devices will drift by minutes per day. I know there are issues with time on VMs, but I was hoping using the Meinberg NTP service ...
8
votes
7answers
3k views

Local or public NTP servers?

For a relatively large network (thousands of hosts) - what are the arguments for and against running a locally managed (pool of) NTP server(s) (perhaps periodically set via some public NTP server) and ...
4
votes
1answer
77 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 ...
0
votes
0answers
30 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 ...
3
votes
2answers
354 views

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 ...
1
vote
1answer
46 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 ...
2
votes
2answers
80 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
votes
1answer
205 views

Multiple NTP Server Instances on One Server (Linux)

Is it possible to run multiple NTP server instances on the same system? We're using CentOS for our NTP system and want to synchronize specific time depending on what interface the client comes in on. ...
-3
votes
2answers
53 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
51 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 ...
5
votes
4answers
1k views

NTP fudge network source stratum

Is it possible to configure ntpd to fudge the stratum level of a network source? Upon first glance, I thought the fudge directive could accomplish this, however after browsing the ntp.conf(5) man ...
3
votes
1answer
2k views

How can I disable NTP in pfsense?

I am running my pfSense gateway in a ESXi server. right now the server gets its time from the NTP server specified in the general settings section of the WebGUI. I want to disable this so pfSense ...
3
votes
1answer
73 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
182 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
71 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
130 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
507 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
103 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 ...
4
votes
2answers
2k 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 ...
4
votes
1answer
260 views

NTP sync time frequently on Windows 7

I have several Win7 64bit configurations - local dev machine, remote server, VPS. I'm running time sensitive tasks on all of them, therefore I need Windows Time service to: Sync Sync well ...
4
votes
3answers
4k views

NtpClient will wait 3473457 minutes (over 6 years!) before it will do a new attempt of DNS resolution, eventid 134

I find the message hilarious and at first I thought it was some joke from an over-active programmer of the MS team, or a hoax. However, the message appears again and again, a couple of times a day: ...
1
vote
2answers
1k views

enable/disable ntp service on ubuntu 12.04

Our application runs on Ubuntu 12.04 Precise. On this server, we have both ntpdate and ntp. How to enable and disable the NTP service on-demand? I tried # sudo update-rc.d -f ntp remove/default ...
1
vote
0answers
184 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 ...
0
votes
2answers
131 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
vote
1answer
91 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
56 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
votes
0answers
36 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
235 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
65 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
46 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 ...
5
votes
3answers
2k views

DDOS using ntp server

I've heard about new kind of DDOS where ntp is used for reflection . My questions are really simple : Can you please give details on how they work and clarify? Since ntp is ran over UDP, I suppose ...
1
vote
0answers
100 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
78 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 ...
2
votes
4answers
4k views

ntpdate works, but ntpd can't synchronize

This is in RHEL 5.5. First, ntpdate to the remote host works: $ ntpdate XXX.YYY.4.21 24 Oct 16:01:17 ntpdate[5276]: adjust time server XXX.YYY.4.21 offset 0.027291 sec Second, here are the server ...
0
votes
1answer
76 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 ...
0
votes
1answer
2k views

NTP local query always times out

I have a CentOS 6.4 server, it does not have any iptable rules, it runs NTP daemon as service using the following configuration: driftfile /var/lib/ntp/drift server 0.pool.ntp.org server ...
1
vote
4answers
436 views

Setting time back on a production linux server

I am having an issue with the time on a production linux server being 2 hours fast. I need the time to be accurate for a particular project I'm working on, but am a little nervous to change it, as I'm ...
3
votes
1answer
71 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 ...
2
votes
2answers
95 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 ...