In which Oracle credentials file can the port number be found?

The port number is found in the tnsnames.ora file, which is used in Oracle databases to provide network connectivity through Oracle Net Services. This file contains definitions of database service names and includes information such as the host, port number, and service name for each database to which a client might connect.

When a client application wants to connect to an Oracle database, it will reference this file to locate the correct database service. The port number defined within tnsnames.ora indicates the specific listener port that the Oracle database is using to accept incoming connection requests.

In contrast, the other files listed serve different purposes. The sqlnet.ora file is configured for client and server communication settings, such as security and authentication parameters, but does not specify the port number for database connections. The listener.ora file defines the Oracle listener configuration, including the port that the listener is using to listen for incoming connections, but it does not define connection details for specific client applications like tnsnames.ora does. Lastly, init.ora is an initialization parameter file for starting up an Oracle instance, containing various parameters for configuring the database environment but does not contain connection details or port numbers.