%% You should probably cite rfc7672 instead of this I-D. @techreport{ietf-dane-smtp-with-dane-02, number = {draft-ietf-dane-smtp-with-dane-02}, type = {Internet-Draft}, institution = {Internet Engineering Task Force}, publisher = {Internet Engineering Task Force}, note = {Work in Progress}, url = {https://datatracker.ietf.org/doc/draft-ietf-dane-smtp-with-dane/02/}, author = {Viktor Dukhovni and Wes Hardaker}, title = {{SMTP security via opportunistic DANE TLS}}, pagetotal = 18, year = 2013, month = oct, day = 21, abstract = {This memo describes a protocol for opportunistic TLS security based on the DANE TLSA DNS record. The protocol is downgrade resistant when the SMTP client supports DANE TLSA and the server domain publishes TLSA records for its MX hosts. This enables an incremental transition of the Internet email backbone (MTA to MTA SMTP traffic) to TLS encrypted and authenticated delivery.}, }