Set the filter to agressive, it scans the emails. However it is SpamAssassin based and some spam mailers are figuring ways around it between updates, so it has some holes, as does any solution.
the only spam filtering is NOT via white and black lists, that is just an option, it is not the only filter.
the only spam filtering is NOT via white and black lists, that is just an option, it is not the only filter.