Subject: [ietf-smtp] SMTP Status codes

From: Geethapriya Liyanage <[email-masked]>
Date: Thu, 05 Sep 2019 08:05:44 +0530

The RFC3463 defines new mail system status codes.  However, the
excising mail servers are still using old status codes. Is there a work
happening to change the current mail systems status codes according to
this RFC.

Thanks 
Geethapriya

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From: Keith Moore <[email-masked]>
Date: Thu, 5 Sep 2019 00:15:22 -0400

On 9/4/19 10:35 PM, Geethapriya Liyanage wrote:

> excising mail servers are still using old status codes. Is there a 
> work happening to change the current mail systems status codes 
> according to this RFC.

As you have observed, there are two kinds of mail codes.   SMTP "reply 
codes" are 3 digits long:  2xx is normal, 4xx is temporary failure, 5xx 
is permanent failure, and so on.   Those reply codes have been with us 
since at least RFC 821 and have not changed (except that a few new codes 
have been added).   Those codes affect the SMTP state machine - they 
tell a client, for instance, whether it can continue the SMTP dialog or 
whether it should abandon attempts to send the message.

The RFC3463 "enhanced status codes" (note the subtly different name) are 
intended to provide more detail for delivery and non-delivery reports 
(also known as "message disposition notifications" or MDNs), and to be 
language-independent.   There's never been an intention to change the 
SMTP reply codes, because this would break existing SMTP clients.   But 
there is an SMTP extension called ENHANCEDSTATUSCODES that allows an 
SMTP server to return an enhanced status code to a client, for use in an 
MDN.

When designing the MDN format we realized that the 3-digit SMTP reply 
code scheme didn't allow for enough different codes to reflect the 
different reasons for message delivery failure, so we needed a new scheme.

Sorry the similarity between the names is a bit confusing.   In 
hindsight we probably could have made that a bit clearer.

Keith

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From: Geethapriya Liyanage <[email-masked]>
Date: Thu, 05 Sep 2019 17:21:31 +0530

Thank you Keith.  It is clear now. 
Regards,
Geethapriya 
On Thu, 2019-09-05 at 00:15 -0400, Keith Moore wrote:
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