How does filtering in Compatible Systems devices react if a manufactured fin packet is received to elicit a response from a firewall, router, or host?
A. In general, a fin packet does no harm to the router or firewall and only is passed through if the device is configured to permit the packet through. In its default configuration, the IntraGuard silently drops the packet. This action is logged and kept in the reject table for five minutes. In a router, the static (standard) IP filtering code must be configured to drop the packet. The router must be configured with a broad filter to deny all packets, either from the sending host to the receiving host, to the destination port from the source port, or any combination of these conditions.
