This configuration parameter specifies whether to cache negative DNS responses. A negative response is returned when a DNS server is not found. By storing a negative result in the cache, the agent does not look for a server that was previously not found.
Set this parameter to true to cache negative DNS responses or false to not cache negative responses. When this parameter is false, the system attempts to respond to all requests. A cached response expires after the amount of time specified by the dns.cache.timeout parameter (default value is 300 seconds).
The default is true; for example: