Modbus Preprocessor

The Modbus preprocessor is a Snort module that decodes the Modbus protocol. It also provides rule options to access certain protocol fields. This allows a user to write rules for Modbus packets without decoding the protocol with a series of "content" and "byte_test" options.

Modbus is a protocol used in SCADA networks. If your network does not contain any Modbus-enabled devices, we recommend leaving this preprocessor turned off.