모든 디바이스

timedatectl set-timezone Asia/Seoul

vi /etc/ntp.conf

### vi ###
server 3.3.3.3
### vi ###

systemctl restart ntp
systemctl status ntp

ISPLNX

vi /etc/ntp.conf

### vi ###
server 127.127.1.0
fudge 127.127.1.0 stratum 1
### vi ###

systemctl restart ntp
systemctl status ntp