[dns-wg] DNS RMX records - e-mail sender authorization

Hi, I don't know whether this was discussed on this mailing list before. I just subscribed and would like to hear your opinion about http://www.ietf.org/internet-drafts/draft-danisch-dns-rr-smtp-03.txt which describes the RMX records, a method to store authorization records about who is authorized to send e-mails with sender addresses of the zone. It is intended to protect against spam, worms, and such rubbish. regards Hadmut