MatrikonOPC Sniffer is FREEWARE and can be distributed openly. It is a fully functioning application without restrictions.
For integrators installing and configuring OPC, MatrikonOPC Sniffer is an objective investigator for
troubleshooting OPC client/server interoperability issues. MatrikonOPC Sniffer does away with finger-pointing when OPC servers and clients don't communicate properly. It seamlessly logs the activity between OPC servers and clients to isolate interoperability issues and help solve problems quickly and easily.