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

4
votes
1answer
1k 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
vote
1answer
87 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 ...
-3
votes
2answers
223 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
185 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
742 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
2k 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
200 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
1k 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
563 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
336 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
457 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
1k 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
270 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
129 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
41 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, ...
1
vote
2answers
1k 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
80 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
71 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
votes
2answers
397 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
0answers
178 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
221 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
236 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
182 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
6k 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
180 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
290 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
375 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
289 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
8k 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 ...
2
votes
1answer
1k views

Disable NTP on Juniper SRX-240

I'm trying to shutdown/disable the ntp daemon running on a Juniper SRX-240 (junos 11.4), but the obvious solution is apparently not valid for this hardware/software combination.
4
votes
5answers
2k views

How can I defend against a DRDoS exploiting NTP server on an ESXi host?

Recently, we had some problems with one of our ESXi servers, caused by the NTP Server DRDoS Amplification Attack using ntpdc. How do I configure the NTP server on ESXi to not be exposed to this DDoS ...
0
votes
0answers
1k views

Ubuntu 12.04 LTS ntp not working

I'm having major woes trying to get ntp working on several ubuntu 12.04 servers. Note this is NTP to keep the time set on those servers. Not to distribute the time! I've installed several of those ...
2
votes
2answers
3k views

Why does NTP daemon keep listening on UDP6?

I have a clean Debian 7 installation, and I manually entered the following lines in /etc/ntp.conf: interface ignore wildcard interface listen <local_nic_ip> Hoping that NTP will no longer ...
1
vote
1answer
694 views

ESXi host time not syncing with NTP servers

I have 2 NTP servers (AD 2003 machines) and some ESXi hosts, which are configured to sync time from these 2 servers. I found the time is not in sync between these hosts and servers. And time in each ...
-1
votes
1answer
173 views

Godaddy fails to properly configure NTP on their node server hosting my VPS

I have a few VPS servers with Godaddy and with every new server I contracted I had to ask them to set up NTP on the node hosting my container. They always did until now. It seems like their ...
1
vote
0answers
37 views

ntp.conf function and format for server keyword

I have 4 redhat boxes that are each sync'ed by their own arbiter gps clock. These are acting as time sources for the rest of my network. Can I include all four boxes in the peer statements in ...
4
votes
3answers
328 views

Usefulness of a new stratum-1 NTP server

A physicist I know that works in a government institution recently commented that they have a cesium clock, and they were considering the possibility of setting up a public stratum 1 NTP server ...
2
votes
1answer
2k views

ntpdate failing “Name or service not known”

I've got a NAS that is Linux-based (Linux version 2.6.32.11-svn70860) and it is not able to set its time using ntp. The previous SysAdmin is long gone so I have no idea whether this problem just ...
2
votes
1answer
1k views

Linux - NTP stopped working after recent update

A few days ago I had ntp setup on my network, and everything was running fine. One node was set to sync with upstream servers, and the rest of the nodes from the one set to sync upstream. Yesterday I ...
5
votes
3answers
5k views

hyper-v server time sync source - PDC / external NTP?

The environement: 10 Hyper-V hosts, all AD joined a lot of VMs AD joined and some not some AD DCs including PDC as Guests What You think is the best approach to time sync a hyper-v farm with AD ...
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 ...
2
votes
2answers
358 views

ntp server that syncs with other ntp servers but supplies a modified utc

Question We need to create an ntp server that syncs against other ntp servers but gives its client a modified utc. For example, it will receive utc 5:17 pm but it's clients will receive utc 7:17pm. ...
0
votes
3answers
455 views

Time synchronization in Active directory

I've got issues with time synchronization in a domain. I have DCs that spans time zones, however the PDC is located in a time zone where daylight savings is active, this caused all the additional DCs ...
10
votes
2answers
268 views

why doesn't ntp recover after an Internet-less startup?

I have a few Linux devices (without TOY chips, so they completely rely on ntp) which may boot without access to Internet (the link to the switch is up). The ntp service will start but obviously no ...
0
votes
2answers
4k 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 ...
10
votes
2answers
438 views

Linux kernel detecting wrong processor frequency

After a cold boot of a 6.0.8 Debian server (HP ProLiant), ntpd played havoc with system time: offset and jitter with respect to the usual and reliable reference time servers growing without limit. ...
0
votes
1answer
331 views

Gentoo server time issue, can't manually set time, NTPD won't correct, too big of a time difference

So, my server is living in the future, unfortunately I can't get lottery numbers, or stock picks out of it. It thinks this is the time: Thu Nov 7 04:07:18 EST 2013 Not correct, I tried to set the ...
3
votes
2answers
155 views

Setup NTP on Debian

I installed ntp on my debian system: apt-get install ntp ntpdate ntp-server. My questions: How often is the time synchronized - is there a schedule? Is there a log that says when the time was ...
2
votes
1answer
720 views

Which NTP source should I use in ESXi virtual machines?

I have a ESXi host running ~20 virtual machines (mostly EL6, but also one or two Windows Server 2008 R2). What is the best practice for timekeeping on virtual machines? I'm thinking about 3 ...
2
votes
3answers
379 views

Allow NTP to update by large amounts automatically?

Here is my scenario: I run multiple VMs on my workstation to simulate the production environment. At the end of the day I sleep my workstation (with my VMs running in the background) at 6PM. When I ...