DNP3 (Distributed Network Protocol 3)
DNP3 (Distributed Network Protocol 3) is a communication protocol used across electric, water, gas and other utility SCADA systems to carry readings and control commands between a master station and field devices like remote terminal units (RTUs). It was standardized as IEEE 1815, which added an optional Secure Authentication mode on top of the original, unauthenticated protocol, but that mode is frequently left disabled in the field because it requires extra configuration and key management the original design never assumed. An exposed DNP3 endpoint without Secure Authentication enabled will accept control commands from whoever can reach it over TCP port 20000, the same no-built-in-trust problem that makes Modbus/TCP a recurring finding on industrial networks. AdminKit's Modbus/TCP check targets that sibling protocol directly; DNP3 endpoints sit in the same OT exposure category and deserve the same internet-facing scrutiny.
By AdminKit team, Netbase JSC · Updated