Option Name:negative_dns_ttl
Replaces:
Requires:
Default Value:negative_dns_ttl 1 minutes
Suggested Config:

	Time-to-Live (TTL) for negative caching of failed DNS lookups.
	This also sets the lower cache limit on positive lookups.
	Minimum value is 1 second, and it is not recommendable to go
	much below 10 seconds.