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Re: recap rfc2821bis-01 Issue 17: all contination lines must use same code

2007-04-13 00:49:57
On 2007-04-12 16:44:01 -0400, Robert A. Rosenberg wrote:

At 15:20 -0400 on 04/11/2007, Tony Hansen wrote about Re: recap 
rfc2821bis-01 Issue 17: all contination lines mus:

    (i) Do nothing, leaving the text as is
    (ii-a) Make it clear that the codes may be different and
    that clients are expected to respect the *last* value listed
    (ii-b) Make it clear that the codes may be different and
    that clients are expected to respect the *first* value listed
    (iii) Prohibit different codes and, optionally, suggest
    that it is ok for a client to select one of them and
    assume that all of the others are the same.

[...]

Also, I do not like the optional "Pick One" authority in iii.

That follows directly from the requirement that all codes MUST be the
same. If they are the same, it obviously doesn't matter which one the
client uses. If they are not the same, the server is violating the spec
and the client can do what it wants.

If you are going to ignore the LAST result (the only valid one in a
"Here is my result" case when the prior replies are intermediate
status updates [as in the 150 case] as opposed to a single
continuation reply such as the EHLO 250)

(iii) doesn't allow intermediate status updates, so this is moot.

you should verify that all the codes are the same and error out if
they are different.

If such a requirement is written into the RFC, it should also describe
what the the client is supposed to do in case of different codes.
Permanent error? Temporary error? Also, must the reply codes be exactly
the same? Consider something like:

250-Accepting message
251 Forwarded to <foo(_at_)example(_dot_)net>

A client looking at either the first or the last code sees a 2xx code
and concludes that the message has been accepted. A client which
compares the codes must decide whether 250 and 251 are "equal enough"
and if they aren't what kind of error it should report.

        hp

-- 
   _  | Peter J. Holzer    | I know I'd be respectful of a pirate 
|_|_) | Sysadmin WSR       | with an emu on his shoulder.
| |   | hjp(_at_)hjp(_dot_)at         |
__/   | http://www.hjp.at/ |    -- Sam in "Freefall"

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