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

2007-04-12 11:17:36

On Tue, Apr 10, 2007 at 11:24:18AM -0400, Jeff Macdonald wrote:

On Tue, Apr 10, 2007 at 10:40:52AM -0400, John C Klensin wrote:
    (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.


While some may believe the current spec is clear enough, I've seen
individuals outside of this group that have been confused as to what is
valid and I've seen multi-line responses were different codes have been
used. So, the current spec isn't clear enough IMO. I'll try to dig up
some actual examples.

I have found only 1 live example of this:

550-Unknown user
421 SMTP command timeout - closing connection

It is unclear to me what is happening here. 421 can happen at any time,
but is it ok as part of a multi-line response? I think not.

I also have examples of multiple responses to a command. This is not
directly related to multi-line responses, but I'd like to point it out.
I believe the RFC allows this behaviour, but there seems to be two ways
folks handle rejecting content:

C: \r\n.\r\n <-- end of data
S: 5xx
S: 421


C: \r\n.\r\n <-- end of data
S: 421-<long explanation>
S: 421

I think it is out of scope, but should the RFC make a recommendation
either way?

:: Jeff Macdonald | Principal Engineer, Messaging Technologies
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