Ntp server tutorial

Ntp server-Linux general technology-Linux technology and application information. For details, refer to the following section. 1. There are two operating systems: Red Hat 1 and Red Hat 2.
The address of Red Hat 2 is eth0: 192.168.1.3.
The address of Red Hat 1 is eth0: 192.168.1.2.
Setting Method: I set the Red Hat 1 machine to the NTP server and the others to the ntp client. That is to say, the system time of Red Hat 1 and Red Hat 2 is synchronized.
Edit/etc/ntp. conf to add the following content:
Restrict default ignore
Restrict 127.0.0.1
Restrict 192.168.1.2
Restrict 192.168.1.3 mask 255.255.255.0 nomodify
Driftfile/etc/ntp/drift
After writing, Press Esc and save and exit.
Start the ntp service
Service ntpd start
Netstat? Unl | grep 123
Ntptrace 192.168.1.2
Firewall
Iptables-t filter-a input-p udp -- sport 123-j ACCEPT
Iptables-t filter-a output-p udp -- dport 123-j ACCEPT
Time settings
Date DDDDMMMMYYYY
View bios time
Clock? R
Save bios time
Clock? W
Client:
Service ntpd stop
Ntpdate 192.168.1.2
How to prompt
[Root @ localhost ~] # Ntpdate 192.168.1.2
14 Jun 13:58:10 ntpdate [14770]: no server suitable for synchronization found
[Root @ localhost ~] # Ntpdate-d 192.168.1.2
14 Jun 13:40:54 ntpdate [14271]: ntpdate 4.2.2p1@1.1570-o Thu May 14 13:00:58 UTC 2009 (1)
Looking for host 192.168.1.2 and service ntp
Host found: 192.168.1.2
Transmit (192.168.1.2)
Transmit (192.168.1.2)
Transmit (192.168.1.2)
Transmit (192.168.1.2)
Transmit (192.168.1.2)
192.168.1.2: Server dropped: no data
Server 192.168.1.2, port 123
Stratum 0, precision 0, leap 00, trust 000
Refid [192.168.1.2], delay0.00000, dispersion 64.00000
Transmitted 4, in filter 4
Reference time: 00000000.00000000 Thu, Feb 7 2036 14:28:16. 000
Originate timestamp: 00000000.00000000 Thu, Feb 7 2036 14:28:16. 000
Transmit timestamp: d1a172e9.9f771865 Tue, Jun 14 2011 13:40:57. 622
Filter delay: 0.00000 0.00000 0.00000 0.00000
0.00000 0.00000 0.00000 0.00000
Filter offset: 0.000000 0.000000 0.000000 0.000000
0.000000 0.000000 0.000000 0.000000
Delay 0.00000, dispersion 64.00000
Offset 0.000000
14 Jun 13:40:58 ntpdate [14271]: no server suitable for synchronization found