ietf-smtp
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Re: Retry question

2008-08-10 09:37:14

Hector,

Your claims about 5xz return codes in 4.2.5 of 2821bis bring up an interesting interpretation. 4.2.5 also says:

   When an SMTP server returns a positive completion status (2yz code)
   after the DATA command is completed with <CRLF>.<CRLF>, it accepts
   responsibility for:

   o  delivering the message (if the recipient mailbox exists) , or

   o  if attempts to deliver the message fail due to transient
      conditions, retrying delivery some reasonable number of times at
      intervals as specified in Section 4.5.4.

   o  if attempts to deliver the message fail due to permanent
      conditions, or if repeated attempts to deliver the message fail
      due to transient conditions, returning appropriate notification to
      the sender of the original message (using the address in the SMTP
      MAIL command).

Take the following example:

      S: 220 foo.com Simple Mail Transfer Service Ready
      C: EHLO bar.com
      S: 250-foo.com greets bar.com
      S: 250-VRFY
      S: 250 HELP
      C: VRFY Smith(_at_)bar(_dot_)com
      S: 250 <Smith(_at_)bar(_dot_)com>
      C: MAIL FROM:<Smith(_at_)bar(_dot_)com>
      S: 250 OK
      C: VRFY Jones(_at_)bar(_dot_)com
      S: 250 <Jones(_at_)bar(_dot_)com>
      C: RCPT TO:<Jones(_at_)foo(_dot_)com>
      S: 450 Can't send  to him right now
      C: DATA
      S: 354 Start mail input; end with <CRLF>.<CRLF>
      C: Blah blah blah...
      C: ...etc. etc. etc.
      C: .
      S: 250 OK
      C: QUIT
      S: 221 foo.com Service closing transmission channel

According to 4.2.5 above, since Jones(_at_)foo(_dot_)com exists, and foo.com (the server) has sent back a 250 to the DATA command, foo.com (the server) now has responsibility for delivering the message to Jones(_at_)foo(_dot_)com (retrying if necessary) and bar.com (the client) SHOULD NOT attempt to retry delivery to Jones(_at_)foo(_dot_)com(_dot_) Is this the correct interpretation?

[For the record, I think that this is *not* the correct interpretation, as I think you've also incorrectly interpreted the text regarding 5yz responses from DATA: The 2yz or 5yz response from DATA only refers to recipients which themselves got a 2yz response from the RCPT command.]

pr
--
Pete Resnick <http://www.qualcomm.com/~presnick/>
Qualcomm Incorporated - Direct phone: (858)651-4478, Fax: (858)651-1102

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