A system for defending a network against one or more cyber-threats. The system can include a network bus that includes a first node and a second node, such that network traffic flows from the first node to the second node. The system can include an intrusion defense unit connected to the network bus, such that network traffic between the first node and the second node passes through the intrusion defense unit, wherein when a potential cyber-threat is detected in the network traffic, the intrusion defense unit is configured to engage an associated switch to filter the network traffic until the cyber-threat is neutralized.