Ingress Filtering Ingress filtering is a method used by enterprises and internet service providers (ISPs) to prevent suspicious traffic from entering a network. When configured on an edge device such as a router or firewall, ingress filtering examines all inbound packets and then permits or denies entry to the network based on information in the packet header. It is a form of packet filtering. Ingress traffic filtering is one of the first lines of defense in a network security strategy. It i...