sudo apt install ntp
sudo vi /etc/ntp.conf
# 내부망일 경우 Local의 시간으로 설정
# 외부망일 경우 NTP서버 시간 or Local의 시간으로 설정
# 하단의 사진 참고 (Parker_Korea)
# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help
driftfile /var/lib/ntp/ntp.drift
# Leap seconds definition provided by tzdata
leapfile /usr/share/zoneinfo/leap-seconds.list
# Enable this if you want statistics to be logged.
#statsdir /var/log/ntpstats/
statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable
# Specify one or more NTP servers.
#server 1.kr.pool.ntp.org
#server 1.asia.pool.net.org # NTP SERVER
server 127.127.1.0 # Local
# Use servers from the NTP Pool Project. Approved by Ubuntu Technical Board
# on 2011-02-08 (LP: #104525). See http://www.pool.ntp.org/join.html for
# more information.
#pool 0.ubuntu.pool.ntp.org iburst
#pool 1.ubuntu.pool.ntp.org iburst
#pool 2.ubuntu.pool.ntp.org iburst
#pool 3.ubuntu.pool.ntp.org iburst
# Use Ubuntu's ntp server as a fallback.
#pool ntp.ubuntu.com
# Access control configuration; see /usr/share/doc/ntp-doc/html/accopt.html for
# details. The web page <http://support.ntp.org/bin/view/Support/AccessRestrictions>
# might also be helpful.
#
# Note that "restrict" applies to both servers and clients, so a configuration
# that might be intended to block requests from certain clients could also end
# up blocking replies from your own upstream servers.
# By default, exchange time with everybody, but don't allow configuration.
restrict -4 default kod notrap nomodify nopeer noquery limited
restrict -6 default kod notrap nomodify nopeer noquery limited
# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::1
# Needed for adding pool entries
restrict source notrap nomodify noquery
# Clients from this (example!) subnet have unlimited access, but only if
# cryptographically authenticated.
restrict 0.0.0.0 mask 0.0.0.0 nomodify notrap #모든 접근권한 허용
# If you want to provide time to your local subnet, change the next line.
# (Again, the address is an example only.)
#broadcast 10.161.100.255
# If you want to listen to time broadcasts on your local subnet, de-comment the
# next lines. Please do this only if you trust everybody on the network!
#disable auth
#broadcastclient
#만일 이후 동기화가 진행이 안될 시 로봇과 서버의 /var/lib/ntp/ntp.drift 파일 비교
#동일하게 설정할 경우 정상적으로 동기화가 진행됨.
