Set the maximum size for client ids, MQTT v3.1 specifies a limit of 23 characters.
max_client_id_size = 23
This option default to
This option allows persistent clients (those with
clean_session set to
false) to be removed if they do not reconnect within a certain time frame.
The expiration period should be an integer followed by one of
y for hour, day, week, month, and year; or
persistent_client_expiration = 1w
This option defaults to
Limit the maximum publish payload size in bytes that VerneMQ allows. Messages that exceed this size won't be accepted.
max_message_size = 0
0, which means that all valid messages are accepted. MQTT specification imposes a maximum payload size of 268435455 bytes.