NTPサーバー設定

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● NTP サーバーの設定


1) ntp がインストールされているかチェック

[root@localhost ~]# rpm -qa | grep ntp
ntpdate-4.2.4p8-3.el6.centos.i686
ntp-4.2.4p8-3.el6.centos.i686               <-- インストールされている
fontpackages-filesystem-1.41-1.1.el6.noarch


2) インストールされていない場合はインストールする

[root@localhost ~]# yum -y install ntp


3) /etc/ntp.conf の編集

# 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 192.168.1.0 mask 255.255.255.0 nomodify notrap
restrict 192.168.1.0 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  sutns.sut.ac.jp                 # Tokyo Rika Daigaku
server  eric.nc.u-tokyo.ac.jp           # Tokyo Daigaku
server  gpsntp.miz.nao.ac.jp            # Kokuritsu Tenmondai
server  clock.nc.fukuoka-u.ac.jp        # Fukuoka Daigaku
server  ntp2.jst.mfeed.ad.jp

#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
server 192.168.1.2 iburst
restrict 192.168.1.2 mask 255.255.255.255 nomodify notrap noquery


4) 念のために /etc/ntp/ntpservers に上記のサーバーを追加

sutns.sut.ac.jp
eric.nc.u-tokyo.ac.jp
gpsntp.miz.nao.ac.jp
clock.nc.fukuoka-u.ac.jp
ntp2.jst.mfeed.ad.jp


5) ntpd 起動前に ntpdate で時刻を合わせる

# ntpdate sutns.sut.ac.jp


6) 自動起動の設定

# chkconfig ntpd on


7) ntpd 起動

# service ntpd start


8) ntpd の状態チェック

# ntpq -p