In that case, I would suggest deploying an IDS with the ability to monitor each of your network segments. Resources permitting, it's a good idea to have the ability to see into each of your zones. This will allow you to monitor traffic that passes between devices within the same zone and never reaches the firewall. Depending upon your data center architecture, it may even be possible to use a SPAN port to provide traffic from more than one zone to the same IDS sensor or network interface card (NIC).
Also consider deploying some intrusion prevention system (IPS) functionality. For more information, read my recent tip entitled "Network intrusion prevention systems: Should enterprises deploy now?".
- Best practices for creating an IDS and maintaining a signature database with Mike Chapple.
- Is it possible to write an IDS using Java? Read more.
This was first published in February 2008