The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.

2.2.6 Network Time Service

If you select to synchronize the data and time over the network, the system is configured as an NTP client that uses the [012].rhel.pool.ntp.org public servers by default. If your systems rely on Kerberos authentication, which requires close synchronization of the clocks on each participating system, you might prefer to configure your systems to use a local NTP server instead.