Kaiterra Air Quality monitor cannot connect to nanomq

[hrbonz]

Describe the bug
When configuring a Kaiterra Mini air quality monitor (https://www.kaiterra.com/sensedge-mini-indoor-air-quality-monitor) to connect to a nanomq service, the monitor cannot finish the connection. The server with debug log level throws the following:

2025-02-05 15:19:10 [2211] INFO  /home/runner/work/nanomq/nanomq/nng/src/sp/transport/mqtt/broker_tcp.c:412 tcptran_pipe_nego_cb: Disconnect Client due to 153 parse CONNECT failed
2025-02-05 15:19:10 [2211] ERROR /home/runner/work/nanomq/nanomq/nng/src/sp/transport/mqtt/broker_tcp.c:465 tcptran_pipe_nego_cb: connect nego error rv:(13)

The monitor works perfectly when connecting to mosquitto.
Kaiterra monitors are deployed all over the world (this model and others).

Expected behavior
The monitor should be able to initiate a connection and send data.

Actual Behavior
The connection doesn't complete and the monitor goes into a retry loop.

To Reproduce
N/A

** Environment Details **

• NanoMQ version: NanoMQ Messaging Engine for Edge Computing & Messaging bus v0.23.2-2
• Operating system and version: debian 12 bookworm
• Compiler and language used
• testing scenario

Client SDK
No idea as this is what comes from the monitor

Additional context
I used tcpdump to make a network capture during the connection, maybe that can help.

# tcpdump -i ens18 -n "tcp and port 1883" -XX -w kaiterra_mini_nanomq.pcap
# tcpdump -r kaiterra_mini_nanomq.pcap -XX
reading from file kaiterra_mini_nanomq.pcap, link-type EN10MB (Ethernet), snapshot length 262144
17:53:08.467785 IP Kaiterra-SE-200-08CE06.54983 > cleverhub.1883: Flags [F.], seq 1053186, ack 4196577692, win 13999, length 0
        0x0000:  bc24 11ab 6794 44ef bf08 ce06 0800 4500  .$..g.D.......E.
        0x0010:  0028 0369 0000 ff06 d145 c0a8 32da c0a8  .(.i.....E..2...
        0x0020:  32f6 d6c7 075b 0010 1202 fa22 b19c 5011  2....[....."..P.
        0x0030:  36af f60e 0000 0000 0000 0000            6...........
17:53:08.467806 IP cleverhub.1883 > Kaiterra-SE-200-08CE06.54983: Flags [.], ack 1, win 64200, length 0
        0x0000:  44ef bf08 ce06 bc24 11ab 6794 0800 4500  D......$..g...E.
        0x0010:  0028 0000 4000 4006 53af c0a8 32f6 c0a8  .(..@[email protected]...
        0x0020:  32da 075b d6c7 fa22 b19c 0010 1203 5010  2..[..."......P.
        0x0030:  fac8 31f5 0000                           ..1...
17:53:09.468014 IP Kaiterra-SE-200-08CE06.54984 > cleverhub.1883: Flags [S], seq 1074299, win 14000, options [mss 1400], length 0
        0x0000:  bc24 11ab 6794 44ef bf08 ce06 0800 4500  .$..g.D.......E.
        0x0010:  002c 036a 0000 ff06 d140 c0a8 32da c0a8  .,[email protected]...
        0x0020:  32f6 d6c8 075b 0010 647b 0000 0000 6002  2....[..d{....`.
        0x0030:  36b0 37e2 0000 0204 0578 0000            6.7......x..
17:53:09.468039 IP cleverhub.1883 > Kaiterra-SE-200-08CE06.54984: Flags [S.], seq 536526330, ack 1074300, win 64240, options [mss 1460], length 0
        0x0000:  44ef bf08 ce06 bc24 11ab 6794 0800 4500  D......$..g...E.
        0x0010:  002c 0000 4000 4006 53ab c0a8 32f6 c0a8  .,..@[email protected]...
        0x0020:  32da 075b d6c8 1ffa bdfa 0010 647c 6012  2..[........d|`.
        0x0030:  faf0 e73f 0000 0204 05b4                 ...?......
17:53:09.470308 IP Kaiterra-SE-200-08CE06.54984 > cleverhub.1883: Flags [.], ack 1, win 14000, length 0
        0x0000:  bc24 11ab 6794 44ef bf08 ce06 0800 4500  .$..g.D.......E.
        0x0010:  0028 036b 0000 ff06 d143 c0a8 32da c0a8  .(.k.....C..2...
        0x0020:  32f6 d6c8 075b 0010 647c 1ffa bdfb 5010  2....[..d|....P.
        0x0030:  36b0 715d 0000 0000 0000 0000            6.q]........
17:53:09.470431 IP Kaiterra-SE-200-08CE06.54984 > cleverhub.1883: Flags [P.], seq 1:41, ack 1, win 14000, length 40
        0x0000:  bc24 11ab 6794 44ef bf08 ce06 0800 4500  .$..g.D.......E.
        0x0010:  0050 036c 0000 ff06 d11a c0a8 32da c0a8  .P.l........2...
        0x0020:  32f6 d6c8 075b 0010 647c 1ffa bdfb 5018  2....[..d|....P.
        0x0030:  36b0 94f0 0000 1026 0004 4d51 5454 04c0  6......&..MQTT..
        0x0040:  003c 0016 4b61 6974 6572 7261 2d53 452d  .<..Kaiterra-SE-
        0x0050:  3230 302d 3038 6365 3036 0000 0000       200-08ce06....
17:53:09.470447 IP cleverhub.1883 > Kaiterra-SE-200-08CE06.54984: Flags [.], ack 41, win 64200, length 0
        0x0000:  44ef bf08 ce06 bc24 11ab 6794 0800 4500  D......$..g...E.
        0x0010:  0028 9ebc 4000 4006 b4f2 c0a8 32f6 c0a8  .(..@[email protected]...
        0x0020:  32da 075b d6c8 1ffa bdfb 0010 64a4 5010  2..[........d.P.
        0x0030:  fac8 e73b 0000                           ...;..
17:53:09.470622 IP cleverhub.1883 > Kaiterra-SE-200-08CE06.54984: Flags [F.], seq 1, ack 41, win 64200, length 0
        0x0000:  44ef bf08 ce06 bc24 11ab 6794 0800 4500  D......$..g...E.
        0x0010:  0028 9ebd 4000 4006 b4f1 c0a8 32f6 c0a8  .(..@[email protected]...
        0x0020:  32da 075b d6c8 1ffa bdfb 0010 64a4 5011  2..[........d.P.
        0x0030:  fac8 e73b 0000                           ...;..
17:53:09.472573 IP Kaiterra-SE-200-08CE06.54984 > cleverhub.1883: Flags [.], ack 2, win 13999, length 0
        0x0000:  bc24 11ab 6794 44ef bf08 ce06 0800 4500  .$..g.D.......E.
        0x0010:  0028 036d 0000 ff06 d141 c0a8 32da c0a8  .(.m.....A..2...
        0x0020:  32f6 d6c8 075b 0010 64a4 1ffa bdfc 5010  2....[..d.....P.
        0x0030:  36af 7135 0000 0000 0000 0000            6.q5........

I attached the pcap file here, it can be opened in tcpdump or wireshark (had to add a txt extension)

kaiterra_mini_nanomq.pcap.txt

[JaylinYu]

Sorry about this, this is a frequently asked question.
NanoMQ has a more strict rules upon user name and password. It doesnt allows null username & password because they are not valid UTF-8 format. and some SDK ignore such restriction.
You can try add random password and username, then the issue shall gone.

[hrbonz]

That's good to know, would it make sense to add this to the nanomq docs? I'm not sure which section it should live in but it could help for first timers. I don't mind sending a PR to nanomq if you point me in the right direction.
I installed mosquitto because I needed something to work for tests but wanted to use nanomq as the bridge behaviour in case of connection loss is better IMHO.