query SPF (Sender Policy Framework) to validate mail senders

 The Sender Policy Framework (SPF) is one part of the SPF/SRS protocol
 pair. SPF allows email systems such as Sendmail, Postfix, Exim,
 Zmailer and MS Exchange to check SPF records and make sure that the
 email is authorized by the domain name that it is coming from. This
 prevents email forgery, commonly used by spammers, scammers and email
 viruses/worms.
 .
 This package contains simple utilities that use libspf2 to test and
 query SPF records.