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Seeing this messages indicates a problem with the MQTT client implementation.
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Statement
Client ID: abc, IP:x.x.x.x was disconnected. reason: Sent second CONNECT message.Client ID: abc, IP:x.x.x.x disconnected ungracefully.
Meaning
| Info |
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This disconnect reason implies a protocol violation by the client |
When you see this message, the client got disconnected by the broker because it sent a second CONNECT packet on an already existing MQTT connection.
See MQTT specification.
After a Network Connection is established by a Client to a Server, the first Packet sent from the Client to the Server MUST be a CONNECT Packet [MQTT-3.1.0-1].
A Client can only send the CONNECT Packet once over a Network Connection. The Server MUST process a second CONNECT Packet sent from a Client as a protocol violation and disconnect the Client [MQTT-3.1.0-2]. See section 4.8 for information about handling errors.
Seeing this messages indicates a problem with the MQTT client implementation.
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Statement
Disconnecting client with clientId xxxx and ip xxx.xx.xx.xx forcibly via extension system.
Meaning
This statement occurs when using HiveMQ Enterprise Security Extension, which disconnects the client forcefully when the connected client’s authentication is expired.