利用ntpd搭建本地NTP服务器

安装方法：

yum install -y ntp

配置说明：

vi /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.
# 对于可以连接到本服务器的client拒绝所有的修改时间操作
restrict default 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.
# 指定可以修改本机时间的IP，以下配置表示只有本机能做修改
restrict 127.0.0.1 
restrict ::1

# Hosts on local network are less restricted.
# 指定允许使用NTP服务的网段
#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 iburst		# 指定本机用于同步时间的NTP服务器
server 1.centos.pool.ntp.org iburst
server 0.pool.ntp.org iburst
server 1.pool.ntp.org iburst
server cn.pool.ntp.org iburst


#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

# 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

# Disable the monitoring facility to prevent amplification attacks using ntpdc
# monlist command when default restrict does not include the noquery flag. See
# CVE-2013-5211 for more details.
# Note: Monitoring will not be disabled with the limited restriction flag.
disable monitor

服务控制

systemctl enable ntpd
systemctl start ntpd
firewall-cmd --permanent --add-service=ntp
firewall-cmd --reload
ss -anpu | grep 123

查看同步进程

ntpq -q