Tamas TEVESZ writes ("Re: [Exim] Changing dialogue"):
> On Mon, 14 May 2001, Christophe - ICOR - wrote:
> > Hello, I have problems with mail client and I would like to modify
> > the dialogue with exim.
Your SMTP client is in flagrant breach of the SMTP specification.
RFC2821:
4.2 SMTP Replies
...
An SMTP client MUST determine its actions only by the reply code, not
by the text (except for the "change of address" 251 and 551 and, if
necessary, 220, 221, and 421 replies); in the general case, any text,
including no text at all (although senders SHOULD NOT send bare
codes), MUST be acceptable. [...]
> actually, exim does not need to be modified. smtp replies are solely
> numeric codes, any, read, _any_ text after the numeric code is
> absolutely irrelevant (the only exception from this might be ESMTP,
> where the server has to include the word 'ESMTP' in her banner if she
> is capable of esmtp. iirc. but all other is just numeric).
There is no requirement in the specification for ESMTP to appear in
the banner. RFC2821 and its predecessors (particularly 1869 on ESMTP)
provide a perfectly good mechanism for determining whether an SMTP
server supports ESMTP.
However, the authors of Sendmail (spit) couldn't figure out how to
implement that, so instead they invented the `ESMTP in banner'
convention. 2821 was not promulgated when ESMTP was invented, but
this behaviour is a clear breach of the intent of 821, and a clear
breach of the by-then-well-established RFC1123 `Host requirements':
5.2.10 SMTP Replies: RFC-821 Section 4.2
...
A sender-SMTP MUST determine its actions only by the reply
code, not by the text (except for 251 and 551 replies); any
text, including no text at all, must be acceptable. [...]
Sendmail is crap, film at 11.
However, because Sendmail implements the braindead MIME specs which
say that MTAs have to corrupt the bodies of messages when they send
them to non-ESMTP/MIME hosts, everyone has to kowtow to this one piece
of Sendmail braindamage in order to avoid being clobbered by a worse
one.
Having said all that, Exim is free software. You can make it do
whatever you want - just use the source.
Ian.
