[AMQ-5886] AMQ accepts illegal MQTT protocol level (5, only 3 and 4 are defined)

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 5.11.1
• Fix Version/s: 5.13.4, 5.14.0

Environment

OSX 10.10
https://github.com/ckrey/MQTT-Client-Framework testcases

• Assignee: Timothy A. Bish
• Reporter: Christoph Krey
• Created: 14/Jul/15 17:12
• Updated: 03/Aug/17 08:08
• Resolved: 03/Mar/16 17:47

Description

MQTT spec says:

[MQTT-3.1.2-2]
The Server MUST respond to the CONNECT Packet with a CONNACK return code 0x01 (unacceptable protocol level) and then disconnect the Client if the Protocol Level is not supported by the Server.
[MQTT-3.2.2-5]
If a server sends a CONNACK packet containing a non-zero return code it MUST then close the Network Connection.