Networks & Defense
Edge Device
Also: network appliance, boundary device, perimeter device
A router, firewall, VPN gateway, switch or similar device that sits at a network boundary or faces the internet.
In more detail
Edge devices run vendor firmware, often have no security agent and thin logging, are rarely patched and frequently have no clear owner. Control of one gives an attacker a view of traffic and configuration files that hold credentials, which is why they are favoured targets. Defence starts with an inventory, then reducing exposed services, patching and sending their logs to a central collector.