In most cases, the port number of an Oracle Database component is displayed in the tool used to configure the port.
In addition, ports for some Oracle Database applications are listed in the portlist.ini file. This file is located in the $ORACLE_HOME/install directory.
If you change a port number after installation, that port number is not updated in the portlist.ini file. For this reason, the portlist.ini file is an accurate record of ports configured at the time of installation.