Learning RHEL Networking

Configuring time services on RHEL 7

One of the essential services on your network is the supply of accurate time. This is required for authentication with Active Directory or other Kerberos-based mechanisms and to make timestamps useful in log files.

Network Time Protocol (NTP) uses UDP and the traditional port 123. This protocol dictates the number of seconds that have elapsed since midnight on January 1, 1900. NTP is 32 bit, which means that the maximum time will be reached in 2036; however, as only the difference in timestamps is used rather than the actual time, the date does not present an issue unlike UNIX time ending in 2038, which is a little more serious.

Once the time service is started and synchronized with another time source, the client ...