What Happens When Subscribing to an MQTT Broker with NAT?
Question
When trying to subscribe to an MQTT broker on the internet, the MQTT client is on a private subnet and must be NATed to reach the public broker.
What is the expected outcome when this configuration is in place?
Answers
Explanations
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A. B. C. D.D.
When an MQTT client is on a private subnet and needs to reach a public MQTT broker, the client must be NATed. NAT stands for Network Address Translation, which is a method of remapping a private IP address space to a public IP address space.
In this scenario, the expected outcome would be that the MQTT client periodically reconnects to the broker over the NAT connection. This is because the NAT device, which is likely a router, is translating the private IP address of the client to a public IP address that can be used to communicate with the broker on the internet.
The client will need to establish a connection to the broker over this NAT connection, and since NAT can sometimes cause issues with maintaining long-lived connections, it's possible that the client may need to periodically reconnect. However, this is generally not a significant issue and can be easily handled by the client's MQTT library.
Therefore, the correct answer is C - the client periodically reconnects to the broker over the NAT connection.
