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Re: Minor isn't. It's a pardigm change

2008-03-31 11:36:48

SM wrote:

Hi Paul,
At 02:39 31-03-2008, Paul Smith wrote:
- is going to send a message with the return-path of something(_at_)toaster(_dot_)example(_dot_)org, in which case I'd EXPECT to have an SMTP server running on it, hence an MX record would not be a bad thing, or - is going to send a message with a null return path, in which case what does it matter..

The discussion have been whether the receiver should explicitly specify a MX RR to determine whether it accepts mail. If we stretch the MX RR requirement to a forward and reverse model, then the sender ( also has to have a MX RR. This means that the change affects both senders and receivers. If we use a null return-path, the sender won't know whether there was a delivery failure.

I think that stretching the MX RR requirement to both a forward and reverse model is not something we should necessarily consider. I believe that would change the architecture too fundamentally.

I do stand on the side that MX records should be required for IPv6 only hosts that wish to receive mail at a FQDN.

The reason this must be discussed now, is because if 2821bis is published allowing AAAA fall-back, then we can never* change it in the future.

- Willie

* Obviously by never, I mean that it wouldn't ever happen. That that it theoretically couldn't happen.