Install and configure the NTP service in centos 6.3

Test environment:

Ntpserver 192.168.1.252

Ntpclient 192.168.1.133

 

Preparations:

Disable SELinux:

VI/etc/SELinux/config

SELinux = disabled

Disable iptables:

Service iptables stop

Chkconfig iptables off

 

1. Install the NTP software package:

Yum-y install NTP/* Yum install NTP service */

Chkconfig -- add ntpd/* Add NTP */

Chkconfig ntpd on/* Start NTP at startup */

 

2. Modify the NTP configuration file:

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
Restrict default ignore sets the Default policy to reject all access requests
# 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 cocould
# Be tightened as well, but to do so wocould effect some
# The administrative functions.
Restrict 127.0.0.1
Restrict-6: 1

# Hosts on local network are less restricted.
Restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap allows machine synchronization time in the LAN

# 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
Server 1.centos.pool.ntp.org
Server 2.centos.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 239.415254.254 # manycast Server
# Manycastclient 239.415254.254 autokey # manycast Client

Restrict 0.centos.pool.ntp.org nomodify notrap noquery
Restrict 1.centos.pool.ntp.org nomodify notrap noquery
Restrict 2.centos.pool.ntp.org nomodify notrap noquery

# Undisciplined 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
When the external synchronization source of fudge 127.127.1.0 stratum 10 cannot be contacted, use the local time as the synchronization service.

# Enable public key cryptography.
# Crypto

Includefile/etc/NTP/crypto/PW

# Key file containing the keys and key identifiers used when operating
# With encryption Ric 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 Loops

**************************************** ***********************

Install and configure the NTP service in centos 6.3