my $spf = Mail::SPF::Iterator->new(
$ip, # SMTP Client IP
$mailfrom, # MAIL FROM: mailfrom
$helo, # HELO|EHLO helo
$myname # lokaler Name des Servers
);
my ($result,@ans) = $spf->next;
while ( ! $result ) {
my $answer = ...dns lookup @ans ...
($result,@ans) = $spf->next($answer)
}