Stealth Interface

Stealth interfaces have no IP address. A Screen with stealth interfaces partitions an IP network and controls packet flow between the partitions. Screens containing only STEALTH interfaces are required to have one ADMIN interface for administrative traffic.

Although it acts much like an IP bridge or switch, a Screen with stealth interfaces does not implement the bridging algorithms that detect loops. Make sure that no loops exist in your network configuration where a packet could be sent out from one stealth interface and be received on another. Also note that HA (high availability) clusters require that the machines be connected by means of a non-switching hub.

Stealth interfaces provide a higher degree of security than routing interfaces because they are separate from the standard IP mechanisms used by the operating system. Thus, packets flowing through stealth interfaces cannot inadvertently leak into other network applications running on the system, thereby compromising the security of the firewall.