Networking elements for the Oracle Database server and clients are preconfigured for most environments.

The Easy Connect naming method is enabled by default and does not require a repository. If you use a naming method other than Easy Connect, then additional configuration of Oracle Net Services may be required.

• Database Initialization Parameters for Database Service Registration
  An Oracle Database 19c database service automatically registers with the listeners specified in the LOCAL_LISTENER and REMOTE_LISTENER parameters.
• Net Service Names and the tnsnames.ora File
  The installation process creates a tnsnames.ora file on each node.
• Net Service Names Created by DBCA
  Oracle Database Configuration Assistant creates net service names for connecting to the database instances.
• Listener Configuration and the listener.ora File
  In Oracle RAC environments, Oracle recommends that you let the Oracle Agent manage Oracle listeners for Oracle Databases.
• Net Services Profile File (sqlnet.ora)
  Oracle Universal Installer starts Oracle Net Configuration Assistant (NETCA) after the database software is installed. NETCA creates the Oracle Net Services profile, or the sqlnet.ora file.