NTP Server

Install Chrony to Configure NTP Server for Time Synchronization.

1. Install and Configure Chrony.

[root@onlinebrands ~]# dnf -y install chrony

[root@onlinebrands ~]# vi /etc/chrony.conf

# line 3: change servers to synchronize (replace to your own timezone NTP server)
# need NTP server itself to sync time with other NTP server
#pool 2.centos.pool.ntp.org iburst
pool ntp.nict.jp iburst

# line 24: add network range to allow to receive time synchronization requests from NTP Clients
# specify your local network and so on
# if not specified, only localhost is allowed
allow 10.0.0.0/24

[root@onlinebrands ~]# systemctl enable --now chronyd

2. If Firewalld is running, allow NTP service. NTP uses [123/UDP].

[root@onlinebrands ~]# firewall-cmd --add-service=ntp --permanent
success
[root@onlinebrands ~]# firewall-cmd --reload
success

3. Verify it works normally.

[root@onlinebrands ~]# chronyc sources
210 Number of sources = 4
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^+ ntp-a3.nict.go.jp             1   9   377   291   +937us[ +937us] +/- 8281us
^* ntp-k1.nict.jp                1   9   377   295  -1925us[-2056us] +/- 8056us
^+ ntp-b2.nict.go.jp             1   9   377   286   -180ns[ -180ns] +/-   10ms
^+ ntp-b3.nict.go.jp             1   8   377    25   +478us[ +478us] +/- 9808us