Apple Certified Support Professional Practice Test

The search results in DNS resolution stop when a valid name is found because the purpose of the DNS lookup process is to locate the corresponding IP address for a given domain name. Once a valid IP address is retrieved, further searching is unnecessary, as the desired result has been achieved.

This efficient mechanism ensures that resources are not wasted on additional queries or checks once the information needed is obtained. Other scenarios, such as timeouts or cancellations, may affect the lookup process but do not define the principle that drives it to completion. For example, a timeout would simply indicate that the process can't find a valid answer within a certain timeframe, but it doesn't relate to when the search would traditionally conclude. Similarly, when all domains are checked, if none yields a result, the process might formally stop, but the ideal case is successful retrieval of a valid name before that point occurs.