Re: [Exim] Server Responses

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Author: Exim Users Mailing List
Date:  
To: Exim Users Mailing List
Subject: Re: [Exim] Server Responses
[ On Tuesday, February 12, 2002 at 14:04:18 (-0500), Greg A. Woods wrote: ]
> Subject: Re: [Exim] Server Responses
>
> [ On Tuesday, February 12, 2002 at 12:57:56 (+0000), David Holland wrote: ]
> > Subject: Re: [Exim] Server Responses
> >
> > On Tue, Feb 12, 2002 at 03:43:59PM +0300, Odhiambo G. Washington wrote:
> > > Does anyone know if multiple 220 responses can cause hiccups for other
> > > SMTP servers?
> >
> > RFC2821 implies (in section 4.2) that the initial greeting should be a
> > single line; only replies to commands may be multi-line.
>
> Hopefully you don't mean this phrase, which actually implies the
> opposite to what you're claiming:
>
>     multiline replies are allowed for any command.


BTW, if you meant this part instead:

In ABNF, server responses are:

      Greeting = "220 " Domain [ SP text ] CRLF
      Reply-line = Reply-code [ SP text ] CRLF


where "Greeting" appears only in the 220 response that announces that
the server is opening its part of the connection.

then you're referring to one of the many nasty botches of RFC 2821 -- an
invention the DRUMS committee appear to have dragged out of thin air.

Successful use of multi-line connection greeting replies was done a very
long time before the DRUMS group was even hatched. Nothing in RFC 821
gives any hint that 220 is to be treated specially -- it's just another
server reply and as such any client "MUST" be prepared for a multiline
220 reply.

It is very unfortunately that RFC 2821 does not give a complete ABNF
syntax description as without it it is impossible to clearly interpret
such things. Even the description of multiline replies is seriously
confused w.r.t. other descriptions of reply syntax.

RFC 2821 is one of the worst edited RFCs I've read in a very long time.

--
                                Greg A. Woods


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