S7 Communication (S7comm)S7comm (S7 Communication) is a Siemens proprietary protocol that runs between programmable logic controllers (PLCs) of the Siemens S7-300/400 family. It is used for PLC programming, exchanging data between PLCs, accessing PLC data from SCADA (supervisory control and data acquisition) systems and diagnostic purposes. The S7comm data comes as payload of COTP data packets. The first byte is always 0x32 as protocol identifier. Special communication processors for the S7-400 series (CP 443) may use this protocol without the TCP/IP layers. It can be used as part of Industrial Control System (ICS) or Supervisory Control And Data Acquisition (SCADA) protocol.

This SonicWALL signature identifies legitimate S7comm network traffic.