Unexpected errors in the rabbitmq logs

[vb0om]

Hi everyone!

Environment:
RabbitMQ: 3.13.2
Erlang: 26.2.4

Rabbitmq works correctly, but in the logs regularly see logs like:

2024-05-20 15:26:27.674 | 2024-05-20T12:26:27.674846242Z stdout F 2024-05-20 12:26:27.673081+00:00 [error] <0.24181637.0> missed heartbeats from client, timeout: 60s |  
2024-05-20 15:26:27.674 | 2024-05-20T12:26:27.674710966Z stdout F 2024-05-20 12:26:27.673081+00:00 [error] <0.24181637.0> closing AMQP connection <0.24181637.0> (10.1.0.43:29890 -> 10.10.131.212:5672)
2024-05-20 15:26:20.858 | 2024-05-20T12:26:20.858750581Z stdout F 2024-05-20 12:26:20.856744+00:00 [error] <0.24276971.0> {bad_header,<<3,0,0,44,39,224,0,0>>} 
2024-05-20 15:26:20.858 | 2024-05-20T12:26:20.858699656Z stdout F 2024-05-20 12:26:20.856744+00:00 [error] <0.24276971.0> closing AMQP connection <0.24276971.0> (10.2.0.24:52271 -> 10.10.131.212:5672)
2024-05-20 15:26:14.110 | 2024-05-20T12:26:14.110176825Z stdout F 2024-05-20 12:26:14.109339+00:00 [error] <0.24276336.0> {bad_header,<<3,0,0,47,42,224,0,0>>}
2024-05-20 15:26:14.110 | 2024-05-20T12:26:14.110166876Z stdout F 2024-05-20 12:26:14.109339+00:00 [error] <0.24276336.0> closing AMQP connection <0.24276336.0> (10.1.0.43:42902 -> 10.10.131.212:5672)

I'm very interesting on the exception "{bad_header,<<3,0,0,44,39,224,0,0>>}"
What does it mean?

[lukebakken]

You have a non-AMQP application attempting to connect to port 5672, or perhaps an application is attempting a TLS connection.

[vb0om]

We use application that already has connected to RabbitMQ via tls connection on the port 5671 and everything looks good. I mean messages are consumed by this service.

[lukebakken]

OK, my statement still stands. Something is attempting to open a TCP connection to port 5672, but not establishing an AMQP handshake correctly 🤷‍♂️