NTP server and Client synchronization configuration

NTP server-side configuration (CENTOS7)

A Open the UDP123 Port input-m State--state new-m udp-p UDP--dport 123-j ACCEPT. Then restart the firewall Server service FIREWALLD restart

or directly shut down Firewall service firewalld stop, Chkconfig firewalld off

Two Check that there is no NTP service Rpm–qa|grep NTP, if not then install Yum install–y NTP

Three Network address to sync: vi/etc/ntp.conf

Server 0.centos.pool.ntp.org Iburst

Synchronize native server 127.127.1.0 # Local Clock If you cannot connect to the extranet

Four Set Client IP rights vi/etc/ntp.conf

Restrict 172.22.2.0 mask 255.255.255.0 nomodify notrap

NTP Client synchronization Settings

A. Rathat,centos

First method (the frequency of synchronization time can be controlled by crontab)

1. Close Ntpd:service ntpd stop, Chkconfig ntpd off

2. Can be synchronized with/usr/sbin/ntpdate 172.28.8.190 test

(The time test can be synchronized to the back, from the back to the front, sometimes not )

3.crontab–e * */1 * * * */usr/sbin/ntpdate 172.28.8.190

The second method (can not set the frequency of synchronization time, can be netstat view)

Service ntpd start, Chkconfig ntpd on

Vi/etc/ntp.conf

Server 172.28.8.190

two. SuSE

Visual operations: Control Center--system--date and Time

Three Windows

Visual actions (Internet time settings)

Another: Some statements (under the premise of using the NTPD service)

View the relationship with the upper NTP server ntpq–p

Check to see if you have updated your time Ntpstat

NTP server and Client synchronization configuration