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.

In an Oracle Grid Infrastructure installation, the sqlnet.ora file is located in the following directory by default:

Grid_home/network/admin

For the local listener for the Oracle RAC database instance, the default location of the sqlnet.ora file is $ORACLE_HOME/network/admin directory. In this directory there is a default sqlnet.ora file. Also, you can find a sample sqlnet.ora file in the subdirectory sample.

During installation of the Oracle RAC software, NETCA creates the following entry in the sqlnet.ora file, where $ORACLE_BASE is the path to the Oracle base directory for the Oracle RAC installation:

NAMES.DIRECTORY_PATH=(TNSNAMES, EZCONNECT)
ADR_BASE =$ORACLE_BASE

The parameter NAMES.DIRECTORY_PATH specifies the priority order of the naming methods to use to resolve connect identifiers to connect descriptors.

The ADR_BASE parameter specifies the base directory into which tracing and logging incidents are stored when Automatic Diagnostic Repository (ADR) is enabled for the database.