NTP-Server install in RHEL 6.0

 

***Server ip is= 192.168.122.45***

# yum install ntp ntpdate

#vim /etc/ntp.conf

restrict 127.0.0.1

restrict default ignore

server 0.rhel.pool.ntp.org

server 1.rhel.pool.ntp.org

server 2.rhel.pool.ntp.org

restrict 0.rhel.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery

restrict 1.rhel.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery

restrict 2.rhel.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery

restrict 192.168.122.0 mask 255.255.254.0 nomodify notrap

ntp server synchronization test

# ntpq –p

Output comes like below working fine!

remote           refid      st t when poll reach   delay   offset  jitter

===============================================================

+59.90.134.67    116.193.83.174   3 u   17   64  377   73.294   -8.165  24.050

*segment-119-226 193.79.237.14    2 u   15   64  377   23.212  -75.646  28.411

+ns3.net4india.c 199.167.198.163  3 u    6   64  377   38.989   -9.105  15.379

 LOCAL(0)        .LOCL.          10 l   12   64  377    0.000    0.000   0.001

-----------------------------------------------------------------------------------------------------------

NTP-Client install

# yum install ntp ntpdate

#vim /etc/ntp.conf

restrict default ignore

server 192.168.122.45

restrict 192.168.122.0 mask 255.255.254.0 nomodify notrap

ntp server synchronization test

# ntpq –p

Output comes like below works fine!

remote           refid      st t when poll reach   delay   offset  jitter

===========================================================

*akt-dbtest-svr. 119.226.101.130  3 u   46   64  377    0.191  -36.591  30.653

To synchronize manually with server

#ntpdate –u ntpserverip

Firewall setup

Update your firewall settings, open /etc/sysconfig/iptables.

vim /etc/sysconfig/iptables

-A RH-Firewall-1-INPUT -s 192.168.1.0/24 -m state --state NEW -p udp --dport 123 -j ACCEPT

Save and close the file. Finally, start ntpd:
# service ntpd start
# service iptables restart
# netstat -tulpn