How to prohibit specific IP addresses from accessing Oracle databases

How to prohibit specific IP addresses from accessing Oracle databases
Use sqlnet. the ora file can be used to prohibit the specified IP host from accessing the database, which is of great help to improve the security of the database. At the same time, this technology provides an effective means for us to manage and constrain database access control.
Add the following content to sqlnet. ora:
TCP. validnode_checking = Yes
# Ip tcp. invited_nodes = (IP1, ip2 ......)
# Ip tcp. excluded_nodes = (IP1, ip2 ......)
Then restart the listener.
Note:
1. Both TCP. invited_nodes and TCP. excluded_nodes exist, mainly TCP. invited_nodes.
2. Be sure to permit or disable the IP address of the server's local machine. Otherwise, LSNRCTL will not enable or stop the listener because the process listens.ProgramThe listener is accessed through the local IP address, and the IP address is disabled, but it is not affected when the listener is started or disabled through the service.
3. After modification, you must restart the listener to take effect without restarting the database.
4. Any platform is supported, but only applicable to the TCP/IP protocol.