Setting up NTP synchronization

I come from the Ubuntu context: there installing a package named kind of ntp was generally enough to ensure time synchronization. Today I performed another of my early Rocky Linux installations and I suspect I unintentionally skipped setting an option that would bring that functionality with no other action required. Installing afterwards a package name chrony didn’t help. I might have some firewall between the machine and the external NTP servers, though apparently the first time I installed this matter went smoothly - I did not find the clock set at a presumably GMT time.

How would you achieve such a result?

Thanks in advance!


Chrony uses port udp/323 whereas ntp uses udp/123. So if your firewall does block chrony, then you would need to unblock outgoing access for udp/323.

You can use as an alternative systemd-timesyncd, so:

dnf install systemd-timesyncd

which apparently will use ntp and therefore udp/123. You will of course then need to disable chrony service or remove it, and then enable the systemd-timesyncd service and start it.


I’ve hastily read something about chrony and I may sum up as below.

  • Setting up a chronyd service is the right way to have an automatic synchronization with no need to invoke it with a command line client

  • The mentioned configuration does not imply automatically handling a time server for other hosts

Can you confirm?

Many thanks!


Hi ,
After installing make sure your chrondyd service is running by ( systemctl status chronyd.service)

If service is running check whether client is able to sync time

# chronyc -n sources
MS Name/IP address         Stratum Poll Reach LastRx Last sample
^-                  2  10   377    98   -157us[ -161us] +/- 2961us
^-                  2  10   377    98    +10us[+6011ns] +/- 2928us
^-               2  10   371   427   -363us[ -368us] +/-   49ms
^-               2  10   336   23m   +855us[ +866us] +/-   43ms
^*               3   4   377     9  -4524ns[-5179ns] +/-  424us

Asterisk showing the server with whom client is currently syncing.

Value under Reach column is important. Its should be 377 ( This is in octal , In binary it will be converted to 11111111 ) which literally display the information about last 8 times syncing status ( 1 mean it was successful and 0 mean get failed due to some reason )

Chrony will not change your time zone. If you need to set time zone . you may set by

timedatectl set-timezone Asia/Dubai

you may get the full availbe time zone list by

timedatectl list-timezones