Oracle: Connection Security: of: the security of (trouble) make you cry!

 

1. listener.ora set a specific network address: 0.0.0.0,127.0.0.1 (localhost), nic_ip1, nic_ip2 ...
2. listener.ora set a specific network port: 1521 is certainly not a
3.  sqlnet.ora disposed substantially black list check: tcp.validnode_checking = yes, tcp.invited_nodes = (ip-1, ip-2 ...)
4. database trigger further examination ip, hostname, programe, user, datetime ...
5. Using a virtual network adapter device
6. os firewall: iptables, firewalld
7. Network firewall settings
8. Open only to localhost, then ip-forward
9. ssl encryption: wallet, stunnel
10. ......

 

However, this is not finished, you can set various security combination of the above.