Re: [ietf-smtp] [dispatch] Forced SMTP redirects

[Sam Varshavchik <[e-mail]>]

Viktor Dukhovni writes:

> Postfix has been around since 1997 (alpha), or if you prefer 2001 (1.0 prod).
> The SMTP client in Postfix only ever[1] looks at the first digit.  I expect  
> this
> is fairly common.

Ditto for Courier. The relevant wording in 2?821 never meant anything else  
to me.

   4yz   Transient Negative Completion reply
      The command was not accepted, and the requested action did not
      occur.  However, the error condition is temporary and the action
      may be requested again.

   [ ... ]

   5yz   Permanent Negative Completion reply
      The command was not accepted and the requested action did not
      occur. The SMTP client is discouraged from repeating the exact
      request (in the same sequence).

This is followed by some discussion of the 2nd and the 3rd digit; but none of  
that ammends the concise definition stated above. So far, nobody was able to  
convince me that this means something other than its plain meaning.

I have some dim recollection of very, very few instances, over the last  
several decades, of parties who were (apparently) very much invested into  
having their mail delivered, trying to convince me that someone telling them  
5xx didn't really mean that, because of the specific error message that was  
assigned to the specific numeric code. I never found those arguments very  
convincing.

The most innovating argument revolved around the interpretation of "in the  
same sequence". The argument was that it only means "hey, you just can't  
resend it immediately, but if your RSET, or maybe disconnect or reconnect,  
its okay-dokay".