ietf-smtp
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Re: RFC2821bis-01 Issue 3: EHLO parameter

2007-03-31 11:31:10

Tony Finch wrote:

   However, the server MUST NOT refuse to accept a message for this
   reason if the verification fails: the information about verification
   failure is for logging and tracing only.
[...]
   It is a well-established principle that an SMTP server may refuse to
   accept mail for any operational or technical reason that makes sense
   to the site providing the server.

This is a contradiction. The fix, in line with current practice, is to
downgrade the MUST NOT to a SHOULD NOT - or delete it altogether.

Maybe the intention was something like this:  "Servers SHOULD NOT reject
the Hello with a 5yz reply if the verification fails as a consequence of
getting no cachable DNS reply" (or something less convoluted, allowing a
4yz reply "try again later").

Frank