centos7：搭建ntp时钟服务器-蒲公英云

centos7：搭建ntp时钟服务器

ntp-server:
$ sudo yum install ntp
$ cat /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 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 ::1
    # Hosts on local network are less restricted.
    #restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
    restrict 20.20.20.0 mask 255.255.255.0 nomodify notrap
    server 20.20.20.21
    # Use public servers from the pool.ntp.org project.
    # Please consider joining the pool (http://www.pool.ntp.org/join.html).
    server 0.cn.pool.ntp.org
    server 1.cn.pool.ntp.org
    server 2.cn.pool.ntp.org
    server 3.cn.pool.ntp.org
    #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
$ sudo systemctl start ntpd
$ date
ntp-client:
$ sudo ntpdate ntp-server-ip
$ date