Questions tagged [ntp]

The Network Time Protocol, is used to synchronize system clocks to precision time servers on the internet or locally connected devices such as a GPS.

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Configure ntpd to find local NTP server(s)

I'm currently designing a system (a physical system that can be used where ever) and have run into the issue that on some networks internet NTP servers can be blocked (by a firewall). In those cases ...
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How is ntp 11 minute mode timescale enabled?

My question is about Linux. The hwclock man page states: If the kernel is compiled with the '11 minute mode' option it will be active when the kernel's clock discipline is in a synchronized ...
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ntpdc gets time out

On Debian 9 I have a ntp server, when I run: ntpdc -c dmpeers It ends with: localhost: timed out, nothing received ***Request timed out ss shows: ss -nutpa4 | grep 123 udp UNCONN 0 0 ...
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128 bit timestamp in NTP queries

Wikipedia claims that NTPv4 supports 128-bit timestamps and indeed RFC5905 defines a 128-bit format called "NTP Date Format" in Sect. 6. The RFC says The 128-bit date format is used where ...
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I can’t configure NTP to work with the GPS module as a synchronization source (NMEA + PPS)

I can not configure NTP on Ubuntu 18.04.3 LTS (Linux 4.15.0-74-generic). As a source of synchronization I want to use NMEA + PPS from GPS module. GPS module is connected via USB using the SILABS ...
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How to determine the error of my system clock relative to UTC?

I want to know how 'close' my system clock is to an ideal timescale (like UTC), I'm looking for an output like: "system time is correct to +-12.5ms". My computer runs Arch Linux, and uses the systemd ...
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ntpd config optimization

I have an embedded Linux system without RTC, so it (currently) boots with thinking it's Jan, 1st 1970. I have ntpd installed and started as: /usr/bin/ntpd -g with a pretty standard /etc/ntp.conf: ...
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chrony synchronitation

I have a bunch of rhel servers and I must make sure all of then are synchronized in time. They all are running chronyd service. My question is, is there any utility to check this via a command? Does ...
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ntp won't work on read-only Raspberry Pi

I'm struggling to understand WHY ntp (the service) won't set the time correctly on my raspberry pi. I have configured the filesystem as read only, to save my SD card, but it used to work, and I ...
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Using ntpd for monitoring time drift, but not for adjusting

I would want to use the common ntpd daemon to test whether time is kept by a virtual machine or not, without letting it actually adjust the clock. I'm running Solaris 11.4 (Oracle's standard image ...
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ntpstat showing different servers when run at different times

ntpstat synchronised to NTP server (IP addr redacted) at stratum 5 time correct to within 180 ms polling server every 1024 s If I come back at a later time and run ntpstat, the result will ...
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Understanding vMotion from linux machine

is it possible to understand if vMotion is configured from the Linux OS itself? we ask this because we suspect that chrony service failed on vMotion https://access.redhat.com/solutions/4172631 ...
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Secure way to update Date & Time of a Linux Embedded Device

I have a Linux (4.9.171) machine running on ARM Cortex-A processor. The system has internet connection and talks to my server over SSL. At the first boot, I can configure the date and time to it. ...
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how to build stable NTP server

we have in some room ( with no connection to internet network ) , linux redhat servers we installed the NTP clients based on crhony service on all machines to sync to NTP server now we want to ...
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66 views

is it mandatory to configure the allow in chrony.conf

according to the redhat document - https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/sect-understanding_chrony_and-its_configuration allow ...
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time on machines change after some time in spite chrony service configured

we have machines in cluster before one week we restart the chrony service , and we check the time on all machines after chrony restart time was ok on all machines after 2 days we noticed that on ...
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why does NFS require synchronized system clocks?

In multiple tutorials abouts setting up NFS, there are recommendations about setting up NTP as well to avoid differences between the clocks of the different systems. Do clock drifts affect the file ...
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Using ntpd to perform a one-time sync to an NTP server is taking too long

I have several servers that need to be sync'd to an NTP server on my network. Initially, the time on these servers is relatively close (+/- 5 seconds). My goal is to do a "one-time sync" for each ...
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How does Linux use a real time clock?

I'm investigating a very strange effect on some Beagle Bone Black (BBB) boards. We're seeing occasional jumps of a few months in the system clock which always correlate with systemd-timesyncd ...
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Chrony on RHEL7.2 can sync to windows ntp server, But Chrony on RHEL7.4 can't sync it

according to redhat link: https://access.redhat.com/solutions/3425701 we can see that - Chrony on RHEL7.2 can sync to windows ntp server, But Chrony on RHEL7.4 can't sync it. in my case we have ...
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Adjust System Clock to NTP

Recently installed Debian 10 "Buster" at an old computer here and now it's showing $ date output with 1 hour less. How could be sycronized system time with NTP GMT -3, America/Recife timezone?
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ModuleNotFoundError: No module named 'ntp.ntpc'

I'm building package ntpsec-1.1.3+dfsg1 in buster but failed when compiling. The error is: ModuleNotFoundError: No module named 'ntp.ntpc' I saw that there are some .py files in the package need ntp....
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What do the parameters in the NTP response mean?

When I add the following line to the systemd-timesyncd.service : Environment="SYSTEMD_LOG_LEVEL=debug" I get the following output when syncing the system time: systemd-timesyncd[42507]: Sent NTP ...
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Linux system with no internet connection, dealing with system date

We're developing a vending machine that will run a Xubuntu 18.04 in a Single Board Computer with a browser in kiosk mode, the machine won't be able to connect to the internet on most of the cases. ...
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Why is the /var/log/chrony folder empty?

we are using chrony in order to sync our servers to ntp servers ( redhat 7.2 ) we configured the logdir /var/log/chrony in chrony.conf and restart the chrony ( systemctl restart chronyd ) , but ...
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Why ntpq shows auth bad?

I have two ubuntu 18.04 machines with ntpd ntpsec-1.1.0+419 installed. The ubuntu-1 has access to public internet and it synchronizes time with ntp pools provided by ubuntu like 0.ubuntu.pool.ntp.org. ...
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is it important to set system hardware clock from the system OS

we have redhat 7.2 machines ( some of them are physical machines , and some of them are VM machines ) After my client computers have synchronized with the NTP server, we are thinking to set the ...
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149 views

Local Chrony server and client not syncing

I'm trying to demonstrate a simple Linux local network with some most used services on it. I have two virtual machines (Fedora Server 30): A, B. I have configured A to act as a router in the network ...
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Ubuntu machine time issue

New to ubuntu. I see that my machine has wrong time set in the system. Can some one help how to correct the system time. timedatectl shows Local time: Tue 2019-07-16 03:53:00 IST Universal ...
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ntp + ntp loose synchronize each time in 5:00 morning

we have a very strange behavior we have 12 Linux redhat machines - redhat 7.x two of these VM servers are loosing the time synchronize each day at 5:00 in the morning after we restart the ntp , ...
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230 views

Prevent systemd-networkd (DHCP) from registering (NTP) time servers

I'm trying to stop some SBCs (running Debian) from updating their time via the router's own NTP server. We just want to use a manually configured one such as one from *.pool.ntp.org. I believe the ...
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Ubuntu NTP server: no server suitable for synchronization found

I am synchronizing 4 Raspberry Pi Clocks with an Ubuntu server (all in a local net, connected over ethernet), using NTP. All devices are offline, so the Server just listens to its local clock; The ...
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How to set ntpd server time without referencing another server?

I have an embedded system which synchronizes UTC locally using NTP. One of the clients in the system acts as time reference for the other clients. I guess you could think of it as stratum 0. A program ...
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Feeding “mixed” NMEA to NTP for time correction

I am trying to correct the time on my Raspberry pi by feeding NTPD with GPS nmea data (via serial) and PPS (via GPIO pin) using the following tutorial via shared memory "SHM". http://www.unixwiz.net/...
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Can an NTP client dynamically detect when to try connecting to servers, without integrating with the specific network configuration system?

ntpd handles dynamic network configurations just fine, as does timesyncd; ntpdate never handled dynamic network configurations, and I don't think it makes sense to work around that with scripts ...
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NTP - localhost timeout - source network uses eth0 instead of lo

ntpq -p commands are timing out for me in a centos 6 server. # ntpq -pn 127.0.0.1: timed out, nothing received ***Request timed out tcpdump result shows me that it is using eth0 instead of loopback ...
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How to get timesyncd details?

How can I get detailed information about the NTP status of my system, when using systemd-timesyncd as the time client? The closest one I found is # timedatectl status Local ...
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Update ntp to 4.2.8p13 on CentOS

I have NTP 4.2.6p5 installed on my CentOS 7.5. Due to "Network Time Protocol Multiple Security Vulnerabilities" vulnerability I have to upgrade it to latest NTP 4.2.8p13 version. Now the problem is, ...
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ntpd.pid not getting generated even when ntpd is running in centos7

I have recently upgraded to centos7. I could observe that ntpd.pid is not generated when the ntpd service is started. Earlier, in centos 6, when we start the ntpd service the file ntpd.pid is ...
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Can I install both NTP server & NTP client on same machine (linux)?

Here's my use case : I have 2 independent networks & 3 servers. Server 1 & 2 are connected on Network 1 (172.24.xx.xxx) while Servers 2 & 3 are connected via network 2 (locally : 192.168....
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Cannot disable network time control (NTP)

I want to analyze some protocols (ARP, NDP, etc.) inside virtualbox (OS: Linux Mint 19.1 Tessa) using wireshark and tried to disable the "network time control"-synchronization. yuza@VirtualBox:~$ ...
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Alpine Linux Hangs During Boot at: “ successfully initialized wpa_supplicant”

I installed Alpine Linux on Intel Compute Stick with 32 Bit Atom Processor. After installation I followed the procedure laid out here for connecting to internet via wlan0 port: Connecting to a ...
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systemd: require NTP sync

What should I put in my unit file to ensure my service starts AFTER the time is set via ntp? I have a raspberry pi with a small python script that logs data to a SQL data base. Since the rpi doesn't ...
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ntp using ipv6 address instead of ipv4

I have a laptop running a version of Linux ( 3.12 ). I have ntpd installed and configured to sync with time.google.com. The problem I am having is if I am plugged into a network that only provides ...
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Check ntp server authentication with chronyd client

Is there an alternative for ntpq -c as, while using chronyd as client? While using ntpd as client, ntpq -c as provides details about authentication of client to server using keys.
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ntpd - Why/how is my network getting ntp synchronization while my ntpd is down on its provider?

I was under the impression that the ntpd service is required to be active for my network to be getting ntp data. All of my devices are synchronized to the server's IP, yet when I SSH into the server, ...
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chrony vs. systemd-timesyncd – What are the differences and use cases as NTP clients?

Somehow but not quite building upon the older question "ntpd vs. systemd-timesyncd - How to achieve reliable NTP syncing?", I'd like to ask about the differences between chrony and systemd-timesyncd ...
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Daylight saving in Debian 9

I would like to know how to enable Daylight saving support for Debian 9 with LXDE. My timezone is set to Europe/Rome. However my clock is one hour ahead and - considering Daylight saving - it shouldn'...
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Sync 1pps sync with system clock

We need to use 1pps (gpio source) for timestamp in application. I thought that ntp should be used with the linux pps for this purpose. But the system is standalone without any other servers connected....
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Failed to activate systemd-timesyncd.service

I've scanned all forums and questions and found no working answer to my problem. The Network Time Synchronization service doesn't work. The timedatectl service seems to work just fine without it ...

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