CentOS 타임 서버 ntp 설정 하기

 Server와 Client를 연동 할 경우 시간 오차가 발생 할 수 있다. 강제로 시간을 맞추어 보려고 하였으나, ntp 설정을 할 경우 해결이 가능 하다.

ntp 가 설치가 되어 있지 않는 경우 아래 명령어를 실행 하여 설치 하자.

[whitelife@localhost ~]$ yum install ntp

설정 하기

파일: /etc/ntp.conf

# For more information about this file, see the man pages
# ntp.conf(5), ntp_acc(5), ntp_auth(5), ntp_clock(5), ntp_misc(5), ntp_mon(5).

driftfile /var/lib/ntp/drift

# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
restrict default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery

# Permit all access over the loopback interface.  This could
# be tightened as well, but to do so would effect some of
# the administrative functions.
restrict 127.0.0.1
restrict -6 ::1

# Hosts on local network are less restricted.
restrict 192.168.0.0 mask 255.255.255.0 nomodify notrap

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
#server 0.centos.pool.ntp.org
#server 1.centos.pool.ntp.org
#server 2.centos.pool.ntp.org

server kr.pool.ntp.org
server time.bora.net
server time.nuri.net

#broadcast 192.168.1.255 autokey        # broadcast server
#broadcastclient                        # broadcast client
#broadcast 224.0.1.1 autokey            # multicast server
#multicastclient 224.0.1.1              # multicast client
#manycastserver 239.255.254.254         # manycast server
#manycastclient 239.255.254.254 autokey # manycast client

# Undisciplined Local Clock. This is a fake driver intended for backup
# and when no outside source of synchronized time is available. 
#server 127.127.1.0     # local clock
#fudge  127.127.1.0 stratum 10  

# Enable public key cryptography.
#crypto

includefile /etc/ntp/crypto/pw

# Key file containing the keys and key identifiers used when operating
# with symmetric key cryptography. 
keys /etc/ntp/keys

# Specify the key identifiers which are trusted.
#trustedkey 4 8 42

# Specify the key identifier to use with the ntpdc utility.
#requestkey 8

# Specify the key identifier to use with the ntpq utility.
#controlkey 8

# Enable writing of statistics records.
#statistics clockstats cryptostats loopstats peerstats

위와 같이 설정 파일을 수정 한다.

사설 IP 에 따라서 local network 설정을 192.168.x.x 로 설정 한다.

동기화 하기

[whitelife@localhost ~]$ sudo ntpdate -b time.bora.net

22 Dec 05:47:19 ntpdate[19906]: step time server 203.248.240.140 offset -0.030816 sec