>But that's not what this is about. This is about the user typing in an >email address FOO and that address does not exist, and now some fuzzy >matching will happen for the client/server to map it to a valid address >with no guarantee that the user actually meant that target mailbox.
I'm sorry, but this assertion is completely wrong, and suggests a rather serious failure to understand how mail works. When a mail server handles a locally addressed piece of mail, it maps the local-part of the address into some sort of internal identifier. The local identifier for FOO might be FOO or foo but it's as likely to be user1234. On my system, every case variation such as foO and fOo is an equally valid name for the mailbox. Something like foo+bar or FOO-bar might also be a name for the same mailbox, or might not, depending on how user1234 has configured her mail. Only the mail server knows how it resolves its local-parts which is why for 30 years the spec has said not to guess. The mapping from the local-part to the internal identifier is completely deterministic, and completely opaque to anyone outside. Hence the only way to make this crock work in the DNS is for the DNS server to be able to (conceptually) look inside the mail server for the domain to see what the rules for that domain are. R's, John _______________________________________________ dane mailing list [email protected] https://www.ietf.org/mailman/listinfo/dane
