Henning Schulzrinne wrote: > One of the problems I have seen first-hand is "disappearing" mail. > Example: A webserver sends outbound email directly, but doesn't want > to receive inbound email. The hostname leaks and mail gets sent to > that address, based on the A(AAA) record. What do you mean by "leaks"? If it means something other than the domain name of the webserver appears in the author's rfc2822.From field address (or, of course, the rfc2822.Reply-To field) then your scenario doesn't happen, because those are the only fields that get used for return email from a recipient. Same if/then, with respect to rfc2821.mailfrom and handling notices. If an incorrect domain name is in an author or return handling address, there are bigger problems to solve than AAAA/MX. If you mean yet something else, then what? > The mail is "received", but > disappears into some never-seen /var file. So, a domain name erroneously appears in an address field and the references host erroneously accepts mail it shouldn't. This degree of problematic operation is not likely to get solved with a new DNS construct. If someone is sending out invalid email addresses, then that needs to get fixed, rather than working on some post-hoc mechanism. > Thus, disabling AAAA checking seems to provide much cleaner error > behavior. Reasonable idea. Let's do it for all Internet services, not just email. d/ -- Dave Crocker Brandenburg InternetWorking bbiw.net _______________________________________________ IETF mailing list IETF@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf