CentOS 7 Build NTP server

First step to install NTP

Yum Install NTP

Second step, find the closest time synchronization server

Http://www.pool.ntp.org/zone/asia

The third edition of/etc/ntp.conf

Server 127.127.1.0 iburst # Local Clock when the external time server is unavailable, use the native time as the standard for the time service
Fudge 127.127.1.0 Stratum #这个值不能太高0-15, too high will be an error

Fourth Step

Add an IP segment to allow access

Restrict 192.168.1.0 netmask 255.255.255.0 nomodify notrap

Fifth Step Configuring the firewall

Firewall-cmd--ADD-SERVICE=NTP--permanent
Firewall-cmd--reload

Sixth step to start the NTP service

Systemctl Enable NTPD Boot

Systemctl Start NTPD

Sytemctl Status NTPD

Seventh Step Verification Service

Ntpq-p

Date-r

Eighth step

Synchronizing Remote Time Services

Ntpdate-q 0.ro.pool.ntp.org 1.ro.pool.ntp.org

Nineth step in the client machine synchronization time

Ntpdate-d-B 192.168.85.20

Problems that you may encounter

1 centos stratum 0, Precision 0, Leap xx, trust no server suitable for synchronization found

This problem is due to the firewall blocking the NTP port, use on buy your firewall-cmd command to solve

2 problems with stratum too high

To modify the value of stratum in/etc/ntp.conf

3 NTP boot does not start the workaround

This problem is often due to the 123 ports of the NPT service being caused by other service occupancy, which is typically chronyd

Disabling this service can

Systemctl Disable Chronyd

Build an NTP server for CentOS 7