Hello,
I'm finding for best practices and adequate steps to secure oracle server 11G Enterprise edition and network listener from malicious clients.
Any recommendations? Thank you!

CodePudding user response：

Malicious clients can attempt to flood database servers with connect requests that consume resources. This is a possible scenario for a distributed DoS attack.

To prevent this scenario, use the SQLNET.INBOUND_CONNECT_TIMEOUT in the sqlnet.ora file and INBOUND_CONNECT_TIMEOUT_listener_name parameters in conjunction.

SQLNET.INBOUND_CONNECT_TIMEOUT should be set to a value in seconds and it determines how long a client has to provide the necessary authentication information to a database because it is possible for connections without authentication to stay open indefinitely.
It is also recommended to set a value for the INBOUND_CONNECT_TIMEOUT_listenername parameter in the listener.ora file to determine how long a client has to complete its connect request to the listener after the network connection has been established.

Then database server terminates the connection if the client fails to establish a connection and complete authentication within the time limit. Therefore, to protect both the database server and the listener, Oracle recommends setting both these parameters in combination.