NTP : Configure NTP Server

 Install Chrony to Configure NTP Server for Time Synchronization.

[1]. Install and Configure Chrony.

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

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

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

[root@dlp ~]# firewall-cmd --add-service=ntp --permanent

success

[root@dlp ~]# firewall-cmd --reload

success

[3]. Verify it works normally.

[root@dlp ~]# chronyc sources

210 Number of sources = 4

MS Name/IP address         Stratum Poll Reach LastRx Last sample

========================================================================

^+ ntp-a2.nict.go.jp   1   6    17    26  -3065us[-3065us] +/-   16ms

^* ntp-b2.nict.go.jp   1   6    17    27   -214us[ -910us] +/-   11ms

^- ntp-b3.nict.go.jp   1   6    17    26   +552us[ +552us] +/- 9773us

^- ntp-a3.nict.go.jp   1   6    17    26  +1251us[+1251us] +/- 8182us

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