dave funk dinsytengineeringuiowaedu wed 27 feb 2008 russell jones wrote said right spf look returnpath address address nobody pays attention returnpath look see mail client says email address spf technology intended provide method mtas validate sending address smtp level intial steps smtp protocol mta helohost envelopefrom envelopeto addresses work headers body smtpdata phase usually envelopefrom address interpolated headers returnpath header delivery process dave funk university iowa college engineering 3193355751 fax 3193840549 1256 seamans center sys_adminpostmastercell_admin iowa city ia 522421527 include better better standard better b thu 07 aug 2008 220546 0600 fwd spf_fail flag