AmyMalik
had a dumb idea
AmyMalik
it's for preventing MAIL FROM forgery in i2p and tor, by providing a token system, where the recipient server would hold up the sender, contact the putative sender server's token program, ask the sender server "do you recognize this token?", and it'd give a K for yes, Z for "maybe quarantine it?" or D for no - which would then be used to decide the disposition of the message. Unlike
AmyMalik
with clearnet email, where there's an IP address, and my personal recommended action for SPF fail is to quarantine, I would recommend, for a token exchange fail, that the receiving mailer drop the message, either 4xx 4.x.x for a Z or a "you forgot to turn up your token server", or 5xx 5.x.x barred by sender policy for a D from the token server.