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Re: I-D Action:draft-klensin-rfc2821bis-10.txt

2008-04-24 20:03:58

Robert A. Rosenberg wrote:

Well, an explicit MX does not resolve this problem of a response address not being reachable.

You said that "" is a valid domain so attempts to send to the no-reply address will get to the SMTP server supporting which will then send a "No Such User" reply (which in my book qualifies as reachable since the message to no-reply WAS delivered to the SMTP Server (but then rejected).

My overall point, in so many words, was that mandating an MX record requirement is meaningless IF the GOAL of the mandate is to thwart bad guys.

So even if has a MX record, it means nothing if the other two key parts of the SMTP transaction equation are not valid:

  - Service Port
  - Valid Recipient

At the very least, the service port is a major consideration.

In short, having a MX record does not make you a valid mail host until everything else about the process is valid.


Hector Santos, CTO

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