3.1.2.1 Protocol Name
If the Protocol Name is incorrect the Server MAY continue
processing the CONNECT packet in accordance with some other
specification, but in that case, the Server MUST NOT continue
to process the CONNECT packet according to this specification.
Otherwise the Server MAY respond to the CONNECT Packet with a
CONNACK packet with a DISCONNECT packet containing a
Connect Return Code of 0x84 (Unsupported Protocol Version)
and MUST close the Network Connection.
Non-Normative comment
Packet inspectors, such as firewalls,
could use the Protocol Name to identify MQTT traffic.
Becomes:
A Server which supports multiple protocols uses the Protocol Name
to verify that it has received a CONNECT packet. If the Server does not
want to process the data and wishes to reveal that it is an MQTT Server
it MAY send a CONNACK packet containing a
Connect Return Code of 0x84 (Unsupported Protocol Version) and
then close the Network Connection.
Non-Normative comment
Packet inspectors, such as firewalls,
could use the Protocol Name to identify MQTT traffic.
3.1.2.2 Protocol Version
If this value is not 5, the Server MAY continue processing the
CONNECT packet in accordance with some other specification,
but in that case the Server MUST NOT continue to process the
CONNECT according to this specification.
Otherwise the Server MAY send a
CONNACK packet with a Connect Return Code
0x84 (Unsupported Protocol Version)
and MUST close the Network Connection.
Becomes:
A Server which supports multiple versions of the MQTT protocol
uses the Protocol Version
to verify that it has received a Version 5 CONNECT packet.
If the Protocol Version is not 5 and the Server does not
want to process the data, the Server
MAY send a CONNACK packet containing a
Connect Return Code of 0x84 (Unsupported Protocol Version) and
then close the Network Connection.