sub split_domain {
my $domain = shift;
my ( $sld, $subtld, $tld );
if ( $domain =~ s/\.9\.4\.e164\.arpa$//o ) {
( $sld, $subtld, $tld ) = ( $domain, '', '9.4.e164.arpa' );
} else {
( $sld, $subtld, $tld ) = split /\./, $domain;
( $subtld, $tld ) = ( "", $subtld ) unless $tld;
}
return ( $sld, $subtld, $tld );
}
