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Questions tagged [ntp]

Network Time Protocol, used to synchronize clocks on the Internet.

The NTP is a protocol for synchronizing the clocks of computers based on UDP for clock synchronization of a set of computers in data networks with variable latency. NTP keeps the clock on a computer with the time always right and with great accuracy. Originally conceived by David L. Mills of the University of Delaware and is still maintained by you and a team of volunteers, the NTP was first used before 1985, and today is still very popular and one of the oldest Internet protocols.

257 questions
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How can I check a system's current NTP configuration?

I need to verify the current NTP configuration on some Windows systems. Ideally, I'd like to be able to do this via command line instead of navigating through configuration screens. (I'm working on several different OS versions, and configuration…
Iszi
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Updating Time : ntpdate[3108]: the NTP socket is in use, exiting

The time on my system is incorrect for some reason. i need to run an update but i can't seem to be able to this is the errror. ntpdate pool.ntp.org 31 Aug 12:31:59 ntpdate[3108]: the NTP socket is in use, exiting i just rebooted, i do not know how…
user2735866
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How can I query an NTP server under Windows?

I am not interested in synchronizing my local clock with the remote server. I only want to query it and print the result. I would have assumed that there is a port of ntpq for Windows, but was unable to find any. All other NTP clients I could find,…
Oliver Salzburg
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How to use ntpdate behind a proxy?

Is it possible to use ntpdate behind an HTTP proxy with authentication? In case it is not possible, are there any good alternatives?
Ton van den Heuvel
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NTP - How are NTP servers so accurate

I've noticed that on my servers and other machines the clock always drifts so it has to sync up to remain accurate. How do the NTP server clocks not drift and always remain correct?
Jason
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Mac OS X Date & Time Synchronization

When I have set Mac OS X to set it's date and time automatically, how often is this really done? And is there a way I can force an update?
Svish
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Time wrong when dual-booting Windows and Linux

Ever since I started using Linux in dualboot with Windows I noticed that when I rebooted the machine, the time on the other OS was wrong, e.g. it was 12:00 on Linux, then I rebooted and on Windows it was 18:00, and when I checked the BIOS, the RTC…
arielnmz
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How to know current time from internet from command line in Linux?

How to know current time from internet from command line in Linux? For example, with ntpq program? Not from computer or operating system clock, but from the internet? I don't want to change or to sync the time. I want to just know it.
Dims
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Where do I find the "Internet Time" (NTP) settings in Windows 10?

In Windows 7, you could get to the "Internet Time" settings by following the instructions in this Super User answer. Now, I can get to this interface, but there is no option to set a custom NTP server or even see the current NTP server: I want to…
Deltik
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What are the iptables rules to permit ntp?

My server's clock is wrong because the firewall doesn't permit ntp traffic. What are the iptables rules required to allow the ntp client to get out and back? Any suggestions how to implement those rules on Ubuntu also appreciated.
John Mee
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Determine the time difference between two linux servers

I am troubleshooting a latency network issue on a network. It is probably a nic or cabling issue, but while I was going through the process of figuring it out, I was looking at the timings of a ping packet leaving a network card and arriving at…
Paul
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Where do I find the 'Internet Time' (NTP) settings in Windows 7?

In Windows XP you can get to the 'Internet Time' settings (to select an NTP server or force an update) via the 'Date and Time Properties' in Control Panel. Where is this found in Windows 7? As pointed out, I won't be able to do this if attached to…
pelms
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Why does NTP require bi-directional firewall access to UDP port 123?

From What are the iptables rules to permit ntp?: iptables -A INPUT -p udp --dport 123 -j ACCEPT iptables -A OUTPUT -p udp --sport 123 -j ACCEPT Also, from the NTP website: ... ntpd requires full bidirectional access to the privileged UDP port 123.…
Dawngerpony
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how to check if NTP adjusted system time on Linux?

I have a machine that experienced some troubles with some of the real time stuff that I'm running. One lead that I have is that NTP daemon may have moved the time, causing false timeouts. How do I find out if NTP daemon did indeed move time at all?…
n-alexander
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How to correctly sync time in linux running as virtual guest after host resumes from hibernation?

I use multiple virtual boxes for development and correct time and date is important for me when I push git commits. I do not shut down my host - it runs for months without restarting. I only hibernate it for nights and weekends. This introduces…
SiliconMind
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