Mail::SpamAssassin::RegistryBoundaries - domain delegation rules
Cut a fully-qualified hostname into the hostname part and the domain part, splitting at the DNS registry boundary.
Examples:
"www.foo.com" => ( "www", "foo.com" )
"www.foo.co.uk" => ( "www", "foo.co.uk" )
Cut a fully-qualified hostname into the hostname part and the domain part, returning just the domain.
Examples:
"www.foo.com" => "foo.com"
"www.foo.co.uk" => "foo.co.uk"
Return 1
if the domain is valid, undef
otherwise. A valid domain (a) does not contain whitespace, (b) contains at least one dot, and (c) uses a valid TLD or ccTLD.