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.
332 questions
2 votes
1 answer
88 views
RTC / systemd time drift
I do see the following behaviour on a SUSE SLE 15 VM (VMWare ESXi, location setting is Europe / Germany) and getting confused the more I think about it. I have shortened the journal-log output to the ...
- 278
0 votes
2 answers
63 views
How to send a simple ntp query without updating time when using systemd-timesyncd
Its 2025 and I'm happily using systemd-timesyncd for NTP and time management on Ubuntu. However an embedded device on my network is failing time-synchronisation so I want to test my NTP server is ...
- 261
4 votes
2 answers
2k views
Why is the root distance to my router 2 minutes when pinging it takes 300μs?
I have an Arch Linux system and I am using systemd-timesyncd.service to poll my router for time sync. My router is a MikroTik one with NTP server set up. The router and Arch are connected directly via ...
- 55
1 vote
2 answers
135 views
How can you query the time of the nearest ntp.org NTP server under Debian?
It is well known that by configuring the file /etc/systemd/timesyncd.conf accordingly, you can query NTP servers from a specific country using the following entries, for example: NTP=0.de.pool.ntp.org ...
- 198
1 vote
1 answer
48 views
Comparing Solaris NTP and MacOS SNTP results? Is this accurate time?
What are expected values for offset and jitter from NTP? I have Solaris 11.4 in a VM with NTP configured and am comparing Solaris time stats to my Mac. I notice that MacOS sntp -sS time.apple.com ...
- 155
2 votes
1 answer
269 views
Why the NTP service systemd-timesyncd is not able to synchronize to an offline NTP Server?
NTP Client: configuration of systemd-timesyncd My linux distribution uses the NTP client systemd-timesyncd with the configuration file /etc/systemd/timesyncd.conf: [Time] NTP=192.168.127.11 ...
- 690
5 votes
0 answers
66 views
Units of tick in struct timex
Linux header files and man pages for adjtimex(2) and ntp_adjtime(2) describe struct timex, containing a tick field that is described as the number of microseconds for each system clock tick. However, ...
- 51
0 votes
1 answer
148 views
Is there a way different from restart the systemd-timesyncd service to know the synchronization status between the client and the NTP server?
On my Linux distribution I'm using the NTP client systemd-timesyncd. Test case The test case is: Boot while the system is able to reach the NTP server (that is time1.google.com) by a connection to a ...
- 690
1 vote
3 answers
337 views
How to prove that NTP time sync is checking regularly
How does one prove that systemd-timesyncd is regularly polling the NTP servers to ensure that the system's clock remains "synchronized"? I understand that I can check the yes/no sync'd ...
- 113
0 votes
1 answer
191 views
How to set `iptables` so NTP works while internet access is blocked
I want to configure iptables such that it blocks everything except Date time synchronization over the internet using NTP and Access from machines in the LAN. I wrote the following script: # Reset ...
- 286
1 vote
1 answer
150 views
GNU `make`, modification times, leap seconds and NTP
GNU make relies on timestamps to see if a dependency was changed after some file was built. If you make a change during the leap second or an NTP adjustment, is it possible that make will believe the ...
- 121
0 votes
1 answer
243 views
Chrony NTP: synchronization with an external NTP server in my Docker container works for a few seconds, but after that, synchronization stops working
Time synchronization with an external NTP server in my Docker container works for a few seconds, but after that, synchronization stops working : logs : 2024-09-08T20:54:15Z chronyd version 4.0 ...
- 151
0 votes
2 answers
949 views
NTP client cannot sync date from a specific Server
I want to create a NTP server, and my clients could sync date from this Server. So I add restrict policy in my server, and then restart the NTP service to my it works as a NTP server. Then I add this ...
- 3
2 votes
2 answers
257 views
Why is the ntptrace peers list inconsistent with the ntpq peers list?
Environment: NTP Clients (AIX 6.1 TL07) + P/S NTP Servers (ST1 GPS). Symptom: the ntpq -pn command outputs both the primary and secondary (candidate) NTP server. the ntptrace command just outputs ...
- 335
0 votes
1 answer
212 views
Why is the NTP time off relative to the NIST standard?
The NIST official U.S. time website shows the current UTC and also my device's time and calculates an offset, see attached screenshot: To my surprise the time difference, which varies during the day, ...
- 437