Blackhole Lists
	Ø A Blackhole List is a list of IP addresses Ø What IP addresses are on the list depends on the purpose of the list and the list policies Ø Lists can be populated by scans or nominations or a combination of both Ø Some lists verify entries with tests Ø Some automatically remove hosts Ø Can be used by a mailer to refuse connections from that host Ø Lookups usually implemented in DNS