5.2.5. Rejected and Orphaned Messages

Messages can be explicitly rejected by a consumer. When a message is fetched over a reliable link, the consumer must acknowledge the message for the broker to release it. Instead of acknowledging a message, the consumer can reject the message. The broker discards rejected messages, unless an alternate exchange has been specified for the queue, in which case the broker routes rejected messages to the alternate exchange.

Messages are orphaned when they are in a queue that is deleted. Orphaned messages are discarded, unless an alternate exchange is configured for the queue, in which case they are routed to the alternate exchange.