Most systems have default timeout durations if expected behavior is not achieved. For example, SQL Server has a connection timeout and a command time out. Web services typically have a time out period waiting for a response.
For MSMQ, when I attempt to send a message to an invalid host, I see the message in the originating host's outgoing queue with a state of 'Waiting to connect' and history showing 'Name resolution failed...'.
How long will this stay in the outgoing queues area? Will it ever move to a dead-letter queue? Are there controls to define this duration?