NTP Server Configuration on RHEL 7



Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over Packet, variable-Latency data networks. NTP was originally designed by David L. Mills of the University of Delaware, who still develops and maintains it with a team of volunteers.

NTP is intended to synchronize all participating computers to within a few milliseconds of Coordinated Universal Time(UTC). It uses a modified version of Marzullo’s algorithm to select accurate time servers and is designed to mitigate the effects of variable network latency.

The protocol is usually described in terms of a client-server model, but can as easily be used in peer-to-peer relationships where both peers consider the other to be a potential time source.

Implementations send and receive time stamps using the User Datagram Protocol(UDP) on port number 123. As of June 2010, the current protocol is version 4 (NTPv4).

The NTP program is configured using either the /etc/ntp.conf.

NTP or Open NTPD server software used for configuration.

Client Configuration:

Step 1:-

# yum -y install ntp

Step 2:-

For the one-time synchronization only, use the ntpdate command.

# systemctl status ntpd

Step 3:-

# systemctl stop ntpd

Step 4:-

# ntpdate -b

Step 5:-

Open the NTP configuration file /etc/ntp.conf in a text editor such as vim or nano

# vim /etc/ntp.conf

Step 6:-

server classrrom.example.com(the hostname or IP address of the site NTP server)

Step 7:-

# systemctl start ntpd

Step 8:-

# systemctl restart firewalld

Step 9:-

# netstat

Step 10:-

# systemctl enable ntpd