Implement Oracle Database Firewall using Valid Node Checking



One of the Oracle Database Listener features for protecting your Oracle databases from malicious attacks from unauthorized locations is by implementing the Valid Node Checking (VNC) feature. Through this feature, access to the database can be restricted based on the IP address (or host name) of the client machine attempting to connect to the database. The Oracle database Listener validates the IP address (or host name) of the incoming client machine against the “allow” or “deny” rules specified in sqlnet.ora file before opening up a connection to the database.

Although this is not a new feature and has been available since Oracle8, it has not garnered traction within the Oracle database community mainly due to the following reasons: