Received packet header has invalid packet format

What does ERR_INVALID_HEADER mean?

A received Modbus TCP packet's header had an invalid format. This indicates the packet structure does not conform to the Modbus TCP specification, likely due to a misconfigured or faulty sending device.

• Remote Modbus TCP client sending non-compliant packets or using an unsupported protocol version.
• Application layer protocol mismatch between the client and server.
• Software bug in the sending device generating incorrect packet formats.

Click steps to track your progress.

1. 1

   Verify the remote Modbus TCP client is configured to send standard Modbus TCP packets.

2. 2

   Check for any firmware updates for the remote device that might address known communication issues.

3. 3

   Use a network protocol analyzer to inspect the received packet headers for non-compliance.