Setting NTP Server And Client Fedora 25

NTP Server
    
Install Chrony and Configure NTP server for time adjustment.
Install Chrony.

[root@dlp ~]# dnf -y install chrony
[root@dlp ~]# vi /etc/chrony.conf

# line 3: change servers for synchronization (replace to your timezone's one
#pool 2.fedora.pool.ntp.org iburst
server ntp.nict.jp iburst
server ntp1.jst.mfeed.ad.jp iburst

# line 18: add the network range you allow to receive requests
allow 10.0.0.0/24

[root@dlp ~]# systemctl start chronyd
[root@dlp ~]# systemctl enable chronyd

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

Verify it works normally like follows.
[root@dlp ~]# chronyc sources
210 Number of sources = 2
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^? ntp-b3.nict.go.jp             1   6     1     1  -1186us[-1186us] +/-   10ms
^? ntp1.jst.mfeed.ad.jp          2   6     1     1   -104us[ -104us] +/-   81ms

NTPd

Install NTPd and Configure NTP server for time adjustment.
Install NTPd.

[root@dlp ~]# dnf -y install ntp
[root@dlp ~]# vi /etc/ntp.conf

# line 18: add the network range you allow to receive requests
restrict 10.0.0.0 mask 255.255.255.0 nomodify notrap

# change servers for synchronization (replace to your timezone's one)
#server 0.fedora.pool.ntp.org iburst
#server 1.fedora.pool.ntp.org iburst
#server 2.fedora.pool.ntp.org iburst
#server 3.fedora.pool.ntp.org iburst
server ntp.nict.jp iburst
server ntp1.jst.mfeed.ad.jp iburst

[root@dlp ~]# systemctl start ntpd
[root@dlp ~]# systemctl enable ntpd

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

Verify it works normally like follows.
[root@dlp ~]# ntpq -p

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*ntp-b2.nict.go. .NICT.           1 u    8   64    1   16.572   -2.141   0.398
+ntp1.jst.mfeed. 133.243.236.17   2 u    7   64    1   17.915   -2.236   2.431

NTP Client

It's the time synchronization way on Fedora Client.

[root@client ~]# dnf -y install ntpdate
[root@client ~]# ntpdate dlp.srv.world

23 Nov 15:54:09 ntpdate[2092]: adjust time server 10.0.0.30 offset -0.004505 sec

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