下面是ntp的服务器的配置文件。
目前遇到同步时时间是对的，过一段时间就会慢30分钟。不知与本NTP服务器有关联，本配置文件是否正确麻烦看一下。
# 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 10.200.0.6 mask 255.255.255.0
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server ntp.ntsc.ac.cn prefer
server time.windows.com
server time.nist.gov
server pool.ntp.org
server ntp.neu.edu.cn
server ntp.gwadar.cn
server 0.centos.pool.ntp.org
server 1.centos.pool.ntp.org
#broadcast 10.200.0.6 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
#allow update time by the upper server
restrict ntp.ntsc.ac.cn
restrict time.windows.com
restrict pool.ntp.org
restrict ntp.neu.edu.cn
restrict ntp.gwadar.cn
restrict 0.centos.pool.ntp.org
restrict 1.centos.pool.ntp.org
restrict time.nist.gov
restrict 127.0.0.1
restrict -6 ::1
#undisciplinet 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
