my @nodes = ( "abc.subdomain1.wasweissich.de","def.subdomain1.another.org","ghi.wasweissich.de","abc.subdomain2.wasweissich.de","def.subdomain1.wasweissich.de","ghi.subdomain2.another.org","xyz.another.org" );

my @sorted = map  { $_->[0] }
sort { compare( $a->[1], $b->[1] ) }
map  { [ $_, [ reverse( split /\./, $_ ) ] ] } @nodes;


print "$_\n" foreach @sorted;

sub compare {
    my( $x, $y ) = @_;
    for my $i ( 0 .. ( @$x > @$y ? @$x : @$y ) ) {
        my $c = $x->[$i] cmp $y->[$i];
        return $c unless $c == 0;
    }
    return  1 if @$x > @$y;
    return -1 if @$y > @$x;
    return 0;
}