In which Oracle client credentials' file can we find the port number?

The port number is typically specified in the tnsnames.ora file, which is a configuration file used by Oracle clients to define database connection parameters. This file contains network service names mapped to connection descriptors, which include essential details such as the protocol, host, port number, and service name or SID.

When a client attempts to connect to a database, it refers to this file to find the correct parameters, including the port number defined for the service. The tnsnames.ora file is crucial for Oracle client applications as it provides the necessary information to establish a successful connection.

In contrast, other files listed serve different purposes. For example, ojdbc.properties typically contains JDBC-specific properties for configuring Java applications, truststore.jks is associated with Java's security framework to manage SSL certificates, and sqlnet.ora is used for configuring Oracle Net services within the client environment but does not typically contain the port number directly associated with database service connections.