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

-2
votes
2answers
364 views

NTP server hostname validation regex [closed]

I want make basic syntax validation of NTP server hostnames. (For example, I expect %^$&" is a syntaxticly invalid NTP server hostname.) The reason I want to make this basic validation is because ...
13
votes
2answers
4k views

Why does ntpd listen on so many ports/addresses?

I’ve noticed this for a while, and it’s never made any sense to me: Why does ntpd need to listen on so many addresses? For example, a Debian machine: $ netstat Proto Local Address Foreign Address ...
2
votes
2answers
194 views

Using meinberg ntp over 40Km wireless network

We have a network of 10 clients running Windows XP with meinberg ntp. Clients are syncing with two ntp servers over a 40Km wireless network using mikrotik devices. Some of clients are connecting to ...
8
votes
2answers
10k views

ntpdate and ntpd failing to sync clock on Linux

I have a strange problem with one of my servers. ntpd and ntpdate fail to work, but debugging shows no errors at all. At first I thought maybe a local or network firewall was blocking UDP port 123, ...
2
votes
0answers
3k views

Setting Shoretel phone time correctly with dhcpd

Our Shoretel 230 phones are not picking up time service correctly and thus, the time on the display is wrong. When I go to the diagnostics of the phone, they are using a wrong time server (old). Here ...
0
votes
0answers
1k views

NTP configuration in NEXUS Switch

I'm planning to change the NTP peer to 172.29.100.44, but I'm unable to delete the existing and add new peer NTP peer IP in Nexus switch. Could you please suggest how I can remove the existing ...
3
votes
2answers
206 views

NTP syncs with local timeserver but not NTP pool servers

I setup an NTP server on a machine in another subnet and tried to ync my machine with the server and it works well. But when I try to ust the pool.ntp.org servers (I tried 0.pool.ntp.org, ...
1
vote
0answers
1k views

Does a Juniper SSG work well as an NTP server?

I have an old SSG-140 that I wanted to use as an NTP server for a number of devices - is this device able to act as a stable NTP time source? My Linux clients can't seem to stay synced to the device ...
4
votes
1answer
109 views

NTP devices - Meinberg etc

I am learning about NTP & I was wondering why anyone would buy a Separate Device like the time servers/devices available from Meinberg etc? Can you not run some software which syncs with reputed ...
0
votes
1answer
122 views

Need one time server clock sync for latency test, what should i use ntdate or ntpd

All machines are Ubuntu I need to sync clock one time for all machine in order to do a latency test. I read this article that said - ntpdate is a bit of a blunt instrument - it can only adjust ...
0
votes
1answer
173 views

Why running ntpdate one after one dosnt set offset to 0

I am running ntp update , one after one (with sec between them), In the log i see that there is always an offset , even if update was run few sec ago. Why is that?Is there a chance to get 0 offset? ...
2
votes
1answer
18k views

How to change time source from “Local CMOS Clock” to “DC”

In a domain, I want to set DC as time server. To do that I use this command: w32tm /config /manualpeerlist:europe.pool.ntp.org /syncfromflags:manual /reliable:yes /update and w32tm /resync ...
2
votes
1answer
170 views

Time jumps on guest system really shortly

I've got a ESXI-Server and a OpenSuse 10.3 distribution running on it as a guest system. In a java (6_17) application that uses Thread.sleep() to not hog 100% CPU, I noticed that it sometimes never ...
2
votes
1answer
455 views

Time issues on the Network — How to find the Root Cause

A number of application servers started erroring out in my domain. Troubleshooting led me to a missconfiguration of NTP. I fixed the issue, but I don't know how the issue arose in the first place. ...
4
votes
2answers
1k views

Setting up NTP servers

I have a problem setting up NTP to maintain time on a stand-alone network. This will be an island time-zone. The problem is that the time drifts apart, even after they have been initially ...
0
votes
1answer
9k views

Cisco Switch NTP client Clock is unsynchronized, stratum 16, no reference clock

I am trying to configure a cisco switch as a ntp client, however I cannot get past the show ntp status of Clock is unsynchronized, stratum 16, no reference clock. I've tried setting the clock close to ...
2
votes
2answers
221 views

Crazy VM clock drift

This is taken from an Ubuntu 10.10 VM running on ESX5: Nov 3 21:58:50 server1 ntpd[21169]: adjusting local clock by 31.187370s Nov 3 22:02:36 server1 ntpd[21169]: adjusting local clock by ...
4
votes
1answer
1k views

When should NTPd broadcast/broadcastclient be used instead of client/server or peer modes?

The NTP deamon if often used in its simplest mode, which is client/server: you specify one or more server directives in your ntp.conf and your clients will use those servers. In addition to that, ...
0
votes
1answer
348 views

cannot open shared object file: Permission denied

On a server I haven't installed, ntpd is broken: # /etc/init.d/ntpd start ntpd: error while loading shared libraries: libz.so.1: cannot open shared object file: Permission denied but permissions ...
1
vote
2answers
478 views

Adjust frequency of Windows Time sync

On Windows 2003 it is possible via the registry to set a custom interval for updates. This is done via the following registry key: ...
3
votes
4answers
6k 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 ...
1
vote
2answers
1k views

Setting NTP on Windows 2008 Domain

Our Computers are out by a couple of minutes on the network. I have checked the registry on a computer and found that the type is NT5DS which I believe that it is getting the time from our Domain ...
7
votes
3answers
1k views

NTP Server with no connection to the internet

I have a small LAN that has no connection to the internet. It consists of two ubuntu servers clustered together providing NFS services to two IP cameras. I need to synchronize the time on all the ...
-2
votes
1answer
75 views

how to stop all NTP synchronizations [closed]

I think I have made ​​several ntp settings, and make synchronization across multiple servers on different timezones. On my php scripts, date is displayed randmomly for (+2 , +3 timezone ) , for ...
2
votes
2answers
440 views

Is there any way to make ntpd to iteratively consult the server addresses given in the ntp.conf file?

Suppose the machine has an ntp.conf file that looks like this: driftfile <path-to-drift-file> server <NTP-server-1> server <NTP-server-2> server <NTP-server-2> For some reason, let ...
2
votes
1answer
924 views

Is my NTP configuration correct?

I have a CentOS virtual machine running remotely, accessible via VPN. It was set up to sync time from two servers on the same network. The time set is approximately right, but seems to be drifting ...
5
votes
1answer
2k views

Why should I care about NTP Kernel statistics?

I'ved noticed that munin graphs a few bits of information about timing/kernel statistics that I've never quite understood. Most of my servers seem to stay close to 0, which I presume is good, but one ...
2
votes
2answers
2k views

ntpd on Ubuntu fails to sync with status 2040

My Ubuntu 10.04 server has ntpd running with default configuration. Problem is it doesn't sync. Syslog shows: kernel time sync status 2040 When I try stopping ntpd and running ntpd -q it does ...
10
votes
6answers
826 views

Replacing sick NTP server source and re-synching (with internal time currently 2 minutes late)

One of the external NTP servers (the primary one--currently) we're using as source seems to not be responding to NTP calls. Unfortunately, on our core router (Cisco 6509), the NTP functionality ...
1
vote
1answer
2k views

Access to NTP via IP which doesn't change often

I'm trying to sync the clock of our production server located in a data center with pool.ntp.org. For security reason, our servers has no internet access unless we requested to open specific ip/port ...
2
votes
2answers
10k views

What is my time source server 2003

Have just had a bit of an issue with our time setup after an issue with our PDC. Am on clear up duty now but am struggling with some 2003 servers. On server 2008 I can run w32tm /query /source and ...
2
votes
1answer
159 views

2 servers, times always go out of sync

I have 2 servers set with the same timezone and I set them with the same time and I have them both updating their server time from the same internet time source. But each week they seem to fall away ...
2
votes
1answer
99 views

Procedure for changing system time? [duplicate]

Possible Duplicate: periodically overridding NTP for simulation purposes When we conduct our DR exercises, we have to rerun production batches from the previous day. In order to accommodate ...
3
votes
1answer
486 views

Leap-second flag not forwarded to NTP clients

I'm making some tests with leapfile feature on ntpd to send fake leap-seconds and ensure our Linux platform is resilient to the "bug". The NTP lab is quite simple: a "master" server with local clock ...
5
votes
3answers
230 views

Is an ntpdate correction atomic?

I've got the following in /var/log/syslog, from yesterday (July 30th) Dec 16 22:54:05 omap ntpdate[432]: step time server 91.189.94.4 offset 12052648.821465 sec ntpdate 91.189.94.4 "corrected" my ...
2
votes
1answer
347 views

NTP: ntpdate to sync time between the PCs on a private network

I have two systems. One acts as Primary/Active and has Internet connection and gets time from NTP server. The second system is Secondary/Passive and has no connection to the external world. Primary ...
1
vote
1answer
107 views

How does a replicated DC handles w32tm changes?

We have 2 replicated W2K8R2 DC's. I had updated one (DC1) with w32tm to get manual updates from asia NTP. Everything syncs correctly. My question: (In order to learn): How does this propagates to ...
2
votes
1answer
518 views

Link CentOS server to an NTP Server

I have a CentOS 5.5 server that the clock is wrong on. I also have a pre-existing NTP server, but all of the info I can find is focused on setting up an NTP server, as opposed to linking to one. How ...
7
votes
1answer
2k views

Single NTP server on isolate network

I have two linux machines (A and B) on an isolated network. They must be time-synchronized. Machine A is powered intermittently and must serve the time, as it is connected to an authoritative time ...
1
vote
2answers
4k views

Cisco ASA5505 won't sync with NTP

Today I noticed that the clock my Cisco ASA 5505 firewall was running about 15 minutes late, which surprised me since I've set up the NTP client. My two NTP servers 10.10.0.1 and 10.10.0.2 are ...
2
votes
5answers
3k views

Does CentOS 5.4 properly handle leap seconds?

Apparently the IERS have announced a leap second due at midnight, June 30th this year. Is CentOS/RHEL 5.4 properly updated to support/transition along with updated NTP systems? I was under the ...
-1
votes
2answers
232 views

Is ntp.ubuntu.com redundant?

Does anybody know if Ubuntu's NTP servers are redundant? If I dig them, I get: ;; ANSWER SECTION: ntp.ubuntu.com. 280 IN A 91.189.94.4 vs. when I dig pool.ntp.org: ;; ANSWER SECTION: ...
1
vote
1answer
2k views

ntpd doesn't seem to sync at all

I am following this tutorial It's 2008, so I am very careful using its advice. I need to make this machine the master, and let all other machines use it to sync the time. They are all out of sync by ...
5
votes
2answers
2k views

What is a realistic average time difference between servers in the same LAN?

Until recently, we had at work a small cluster of about 20 small Windows servers (which have now all been virtualized). They were all configured to synchronize with the local time server. It was on an ...
1
vote
1answer
393 views

does NTP minpoll-maxpoll control sync intervals?

Do the NTP minpoll and maxpoll configuration attributes control the sync interval or do they only control the polling interval? where: polling = messaging with NTP servers to estimate the offset ...
1
vote
1answer
1k views

NTP maxpoll limits

Regarding NTP's maxpoll configuration attribute, many resources state: The maximum poll interval defaults to 10 (1,024 s), but can be increased by the maxpoll option to an upper limit of 17 ...
1
vote
2answers
12k views

Windows 7 as NTP Time Server

Trying to get Windows 7 box to act as an NTP Time Server for linux clients From here: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\ In the right pane, right-click ...
2
votes
2answers
6k views

NTP not updating the server time in CentOS

I compiled ntp for arm My NTP client is not updating the time from any of the server I referred to the post "Why is ntpd not updating the time on my server? (7)" But nothing works out.. Here is the ...
2
votes
2answers
322 views

How often does asymmetric latency actually happen?

I was reading through the Wikipedia entry on NTP, and noticed this: The NTP synchronization is correct when both the incoming and outgoing routes between the client and the server have ...
1
vote
1answer
631 views

Windows Server 2008 R2 NTP ignoring SpecialPollInterval

I've pointed the 2k8 machine to the NTP server and it updates fine on the original bootup. But I want it to update every 30 seconds. It's for a practical and I have to show NTP in action. It keeps ...