What it does
ModRadar sweeps a subnet the way a conventional IP scanner does — host discovery, port liveness, reverse DNS — but adds an industrial twist: for every host it finds, it attempts a lightweight Modbus handshake to determine whether the device actually speaks the protocol, on TCP/502 or any port you point it at.
The result is an inventory that distinguishes "a host exists here" from "a Modbus device exists here," which is exactly the distinction that matters when you are commissioning a plant network or auditing an OT segment.
Why we built it
Discovery on industrial networks is usually a manual, error-prone exercise. Generic scanners tell you a port is open; they don't tell you whether the thing behind it is a PLC, an RTU, or a printer. ModRadar closes that gap so engineers can map the Modbus footprint of a network in seconds.
Highlights
- Subnet sweep with host discovery and port liveness
- Active Modbus probing to confirm protocol support, not just an open port
- Reads basic device identification where the slave exposes it
- Fast concurrent scanning, written in Rust
- Plain output that pipes cleanly into other tooling
Status
ModRadar is open source and maintained by Softalink. Contributions and field reports are welcome.