[Top] [All Lists]

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

2021-03-16 18:11:19
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".

Attachment: pgpMECygfXUAe.pgp
Description: PGP signature

ietf-smtp mailing list