Specifying a Connection by Configuring a tnsnames.ora File
By default, when you install an Instant Client, Oracle Universal Installer does not include a sample tnsnames.ora file nor the Oracle Net Configuration Assistant utility normally used to create it.
However, if you want to shield users from having to specify actual host names and port numbers, you may want to consider using a tnsnames.ora file to set the Instant Client-to-Oracle Database connection.
You can create the tnsnames.ora file manually by copying and modifying a version of this file from another Oracle installation, or you can use Oracle Net Configuration Assistant to create and manage it for you.
To install Oracle Net Configuration Assistant: