Close all unused ports

Keep only the minimum number of ports open. You should close all ports not in use.

The Central Designer application uses the following ports:

80—Used when the client applications are separated from the application servers and database server by a firewall, and do not use an SSL connection (HTTP).
443—Used when the client applications are separated from the application servers and database server by a firewall, and use an SSL connection (HTTPS).
1521—Used by the Oracle Listener service.
53000—Used for communication between application servers behind a firewall.