Questions tagged [ntp]

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

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Add a server to a running NTP daemon

I’m willing to add my home NTP server to my running NTP daemon whenever I connect to my home VPN. I’m pretty sure I managed to have this working, several years ago, with a command like ntpdc -c 'keyid ...
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Why open 123/udp in both directions?

When using an NTP server in an environment with a firewall, it is common to open 123/udp in both directions. So my question is, why is it necessary to open it in both directions? For example, when ...
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Latency measurements and PTP

I have a setup with 3 PC's where PC 1 sends data to PC 3 trough PC 2 (all connected trough switch). Im measuring latency for some data packets using Wireshark and to keep all pcs system time in sync ...
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how to test ntp servers as real servers that responding without using ping test

we have bash script that configured the chrony.conf script check if ping is ok on ntp1 and ntp2 ( ntp servers ) and then script insert the ntp servers to /etc/chrony.conf ( only if ping success ) ...
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Shorten the NTP service startup time under no network

I need to create an NTPServer for the MCU without battery to calibrate the time information, I want to calibrate as soon as possible after power on. When I am in a local area network without a network,...
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Raspberry pi can't ping laptop but laptop can ping Raspberry pi

Here's the context to my situation. I'm attempting to setup my rpi zero to use my windows laptop as an NTP server. I have all of the configurations done on both my pi and my windows machine to ...
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How can a Linux server update it's time using Windows Server NTP service?

I have a development server set up without connection to the Internet. (I update it using a makeshift http proxy only when required.) This afternoon, I realized that it's time was off of about 2 ...
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ESXI NTP Synchronization Issues and Firewall

I've noticed recently that my server running ESXI (v7.0 update 2) lost track of time. I've looked up the NTP service and it doesn't seem to working. I provided a lot of details to show my reasoning in ...
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How to test DST when using NTP

We have long-running processes on a server. The server clock is synced with NTP. And RTC is set to UTC. Localtime is set to current DST timezone: $ timedatectl Local time: Thu ...
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How can I see which "Date & time" settings are "hidden or managed by your organization" (and where) [duplicate]

I am on a domain-joined Laptop which cannot connect to the domain controller except once a month or less, so the system time is off by 10 seconds. I can set it manually, but I'd like it to sync to ...
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How to set up a Network Time Protocol (NTP) connection using a Windows server and Linux client?

I am attempting to establish a NTP connection over a network switch between a Windows 10 server and a Linux (Debian 10) client, but the client is failing to synchronise. I can successfully set the ...
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NTP configuration on HP switch mal-function. NTP requests fail

System: HPE OfficeConnect Switch 1820 24G J9980A, Firmware: PT.02.12 (May 2021), OS: Linux 3.6.5, U-Boot 2012.10-00116 (Jul 30 2014 - 10:52:01) The switch connects to ASUS router AC87U. Setup Network \...
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How do I update the Windows 10 NTP time when my machine is in a workgroup and not a domain?

My Windows machine is not on a domain and I need it to update the time from an NTP server. Is there a command to do this when you are not on the domain? At work I use net time /domain:DC1 to set the ...
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How to allow only NTP using iptables?

I'm looking for a way to restrict internet traffic to one of the device on my network so that it can only access NTP an nothing else. Now the easy solution would be to just allow destination port 123 ...
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How can I confirm if the NTP server is working correctly?

In a bid to get my ip camera timing to sync up, I setup an Ubuntu server as a NTP server (https://www.howtoforge.com/tutorial/ubuntu-ntp-server/). I used another pc and tested it as a client and the ...
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Windows time always a few seconds off (w32time), compared to Linux ntp

Usually I don't modify the configuration of my Windows 10 machines regarding time synchronisation. Recently I'm working more with Linux SBCs (Raspberry Pi etc.) on IoT solutions. I noticed how several ...
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Automatic time sync is not working in Windows 10

I have enabled automatic time sync. But time sync is failing in Windows. Fillowing is the screenshot of the error.
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NTP server, port not open

So, I'm trying to install an NTP server on this Windows 10 Home computer. I've tried various tutorials to enable w32time's server mode, and then when that failed I eventually installed Meinberg NTP, ...
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NTP time synchronizes, still shows local time..?

I have set NTP time of Canada (0.ca.pool.ntp.org, 1.ca.pool.ntp.org, 2.ca.pool.ntp.org, as obtained from https://www.pool.ntp.org/zone/ca). The sync server IP is 192.210.199.110 (stratum 2). When I ...
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Debian: Set persistent custom time

I try to set a custom time on my (fresh installed) Debian system. For example, I want to set my time to 2013-05-05. So I disabled NTP on my system with timedatectl set-ntp false, verify that ...
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Enabling dynamic DNS updates in iptables

I have a Debian machine behind a wifi router. The machine is running a cron script to restore connectivity whenever a ping to a pre-defined host fails. I have set up iptables so that only the required ...
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Windows 10 as NTP Server not sending responses

I'm trying to configure my Windows 10 PC to act as an NTP server. I followed the steps here. However, when I look in wireshark, I can clearly see the NTP poll commands coming from the client, but I ...
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Hosting an NTP server on both NICs

I’ve enabled the win32time service to host an NTP server on a machine with two NICs. Each NIC is on a different network. I can query the time server from one of the networks, but not the other. Can I ...
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Why does Windows 10 time service not sync immediately?

After rebooting my PC (Win 10 Pro, 64-bit), I found that my time was off by slightly more than 1s. I have an application that requires the time to be set more accurately than that, so I went into ...
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Changed UTC time dumps after reboot in Arch Linux

I use Arch Linux OS with Linux 5.4.61-1-lts kernel, x86-64. I noticed, that my UTC time is wrong: [tao@dc ~]$ timedatectl Local time: Sun 2020-08-30 12:15:41 EEST Universal ...
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NTPv4 Pool: Origin Timestamp is randomly filled in servers response - why?

The NTPv4 server responses I get from pool.ntp.org servers (requested with chrony 3.5) have random filled values in the 64 origin timestamp field. I can't figure out why. I can't find any information ...
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NTP Time - Get time of remote NTP server in command line

Essentially, I want to get an accurate time from a public NTP server, in DOS or powershell. I know there's the w32tm which can query a remote ntp server, but the result it gives is how much out my ...
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How to find a process that runs hourly

CentOS 7, set it up about 3 years ago, so I might not remember every decision I made... Once an hour, something does a time update. I don't have ntp installed, only ntpdate. Don't have chrony ...
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How do the major OS like Windows, Mac and Ubuntu/Redhat handle DST and time that goes back 1+ hour?

When time is out of sync, I understand most of the modern operating systems have NTP software that do it in smart increments spreading it through a large interval such that it doesn't affect most ...
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Cannot sync with any NTP server on windows 10

I'm trying to sync my windows10 with ANY NTP server but whatever server I use, I'm always receiving timeout. I have tryed setting few different server in "Internet time settings" but in every try i ...
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is there any option ntpq for the ntp server connectivity test like ntpdate -d command?

Is there any option ntpq for the ntp server connectivity test like the ntpdate -d command? ntpdate -d ntpserverip This command shows the suitable ntp server for synchronization. What the ...
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Windows 10 (in a VM) forces time sync/update with setting disabled

I have Windows 10 in a VM to run some tests, some of which require me simulating a different or "wrong" time. However Windows 10 seems to force the clock to the current time despite the Set time ...
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Can I use the IP of an internal private NTP service instead pool.ntp.org spublic service with ntpdate?

I am not so into Linux and I have the following problem syncronzing two Linux machine using ntpdate. I know that I can do it running this command: ntpdate pool.ntp.org that creats the timesync.sh ...
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Unable to sync Windows 10 time with time servers

I have a new, OEM installation of Windows 10 that is unable to contact any time servers to sync the system time. Each attempt gives me a timeout error, and pinging the time server times out as well. ...
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NTPD Service Won't Start on System Boot

Even though ntpd has been enabled, it won't start on system boot. I can issue a "systemctl start ntpd" command that will successfully bring up ntpd, but after reboot ntpd.service goes to inactive (...
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ArchlinuxArm on Raspberry: Can't sync datetime at boot

I have a raspberry pi I use for an irrigation system. The problem is it doesn't have hardware clock so, every time it reboots, the system time is wrong, and I cannot set it to sync it automatically. ...
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Time running out of sync on a CentOS 7 server

i have a problem with one of our webservers running on a CentOS 7. The local and UTC time on the system has been changing for about the last 1 to 2 weeks regularly by several minutes and hours. The ...
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Ways to accurate synchronize clock with linux

I have a computer that doesn't has internet, I put NTP to sync with a USB GPS and serve NTP to other computers. That's working, but sometimes the server is not suitable for synchronization and I need ...
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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 chronyd , ...
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NTP does not syncronize with debian 9.7 and hence date and time are not correct

setup: Client - Debian 9.7 Server - Windows 10 with "Absolute Time server" application running for synchronization Sharing below details NTP deamon process gets started on Debian 9.7 client ...
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Troubleshooting NTP mystery, any ideas?

Task: NTP to a local Synology box (NTP is turned on on the box). Observations (AV and firewall turned off for testing): My C# code (unchanged from when it used to work): Timeout on the receive ...
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Windows "Internet Time" can't reach time server, but w32tm can

This is a very strange problem: I can't synchronize time using the Windows Internet Time dialog, because I get a "Peer is unreachable" or timeout error. Temporarily disabling the firewall doesn't help....
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Windows 10 is ignoring time changes on Samba 4 DC

I have got and VM with a Samba 4 installed as AD DC. It is also NTP server and the time on the server is correct. Tested with ntpdate -q ntp-server, which gives the correct time and date: ntpdate -q ...
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Computer time does not auto update to current time windows 10

I have a table with Windows 10 version 1803 This table attached to a cellular router(meaning the router have SIM inside him to provide the internet). but for some reason the time and date on the ...
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Time accuracy and network performance

Does an inaccurate clock on an router, modem, affect network performance? Today I was troubleshooting videos loading poorly on my PC. During this I decided to look at the statistics on my modem and ...
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Is there any way to validate NTP asymmetric keys

I am working on implementing NTP authentication by asymmetric key (autokey). I just want a way to validate those keys. Is there any utility in ntp-keygen to validate them? Any suggestion is ...
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How to write CMOS time?

I have a fairly new computer (i.e. not likely BIOS battery problem), and every time I boot/reboot the time is off by ~2 seconds. To fix this, I every time have to set my time manually, and then run ...
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Meinberg NTPD for Windows timeouts and not finding files

In my network, I have a reliable NTP server which all PCs are synchronized to. Due to the various problems the Windows Time service is known for (at least in Windows 7 and lower versions), I have ...
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Managed Switch (HP 1820) doesn't synchonise time with NTP Server

I'm trying to set up a managed switch (HP 1820). So far everything works, but the time doesn't synchronise. The switch is configured correctly in terms of the IP-Settings (IP/Sub/Gateway - no DNS ...
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Windows Server and AD - Disable time sync on logon

I have a MS AD domain with some application servers all running Windows Server 2012 R2. The application has a special requirements: time shift between its database and the app servers must be less ...
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