Blacklisting based on SPF

[Julian Yap]

I've noticed some trojans with addresses from usps.com slip through.

Does anyone blacklist based on SPF?

I took a look at the source for SpamAssassin/Plugin/SPF.pm but it only has
evaluation rules for whitelisting:
  $self->register_eval_rule ("check_for_spf_whitelist_from");
  $self->register_eval_rule ("check_for_def_spf_whitelist_from");

Thanks,
Julian