UPnP
UPnP (Universal Plug and Play) is a set of networking protocols that let devices on a local network discover each other and configure services without manual setup, most notably asking the router to open a port-forwarding rule on their behalf. A game console, camera, or video call app can use UPnP's Internet Gateway Device protocol to punch a hole through NAT the moment it needs one, which is convenient but means any device or malware on the local network can request inbound exposure without the owner reviewing or even noticing the new rule. Because UPnP requests are trusted by default and rarely logged, it has repeatedly been implicated in consumer device compromises and in exposing services never meant to be internet-reachable. Routers that support UPnP typically let it be disabled, after which port forwarding has to be configured manually.
By AdminKit team, Netbase JSC · Updated