You must prepare DNS before installing SuperCluster M8 or SuperCluster M7. Installation and the initial configuration cannot proceed until these tasks are finished.
Oracle SuperCluster M8 and SuperCluster M7 Site Checklists
Oracle SuperCluster M8 and SuperCluster M7 Configuration Worksheets
You must register all public addresses, SCAN addresses, and VIP addresses in DNS prior to installation.
Reverse resolution must be forward confirmed (forward-confirmed reverse DNS), such that both the forward and reverse DNS entries match each other.
The SCAN name to the three SCAN addresses must be configured in DNS for round-trip resolution.
Oracle Grid Infrastructure Installation Guide for Linux for additional information about SCAN addresses
Your DNS vendor documentation for additional information about configuring round-trip name resolution