Screened-subnet firewall Wikipedia
In network security, a screened subnet firewall is a variation of the dual-homed gateway and screened host firewall. It can be used to separate components of the firewall onto separate systems, thereby achieving greater throughput and flexibility, although at some cost to simplicity. As each component system of the screened subnet firewall needs to implement only a specific task, each system is less complex to configure.
A screened subnet firewall is often used to establish a demilitarized zone (DMZ).