A device that connects an internal network to an external network is called an _____.

• A. Edge Router
• B. Firewall
• C. Switch
• D. Hub

Answer: (A)

A device that connects an internal network to an external network is a router, specifically an edge router when it sits at the boundary between networks. Routers read the destination IP of each packet and forward it toward its next hop based on routing tables, effectively linking different networks together. At the network edge, this device becomes the gateway between the internal LAN and the outside world, often handling tasks like path selection and sometimes NAT to translate internal addresses for external use.

A firewall focuses on security rules and filtering, not the core job of connecting networks. A switch moves traffic within the same local network by switching Ethernet frames. A hub simply repeats signals to all ports, without any routing between networks. Thus, the edge router is the appropriate term for the device that connects an internal network to an external network.