ports.conf file
The /etc/apache2/ports.conf configuration file stores the directives that determine the TCP ports Apache is listening on. Here is the default content of this file in Ubuntu:
The Listen directive determines the port Apache will bind to. By default this is the port 80. You can change this value to the port of your choice. Just make sure to restart Apache (sudo service apache2 restart) to apply the changes.
The section in the ports.conf file is executed if the module named ssl_module is included.