$protocol = ESMTP: Bug, docu bug or a layer 8 problem?

Mark Martinec Mark.Martinec+amavis at ijs.si
Thu Jan 19 14:23:41 CET 2012


> On 01/16/2012 07:00 PM Mark Martinec wrote:
> > Indeed, a documentation bug.  The 'ESMTP' is not a legal value there,
> > just use 'SMTP'.  Fixing it now...   thanks!
> Hi Mark,
> now I'm a little bit confused, amavisd-new writes ESMTP also in received
> headers:
> Received: from filter.example.com (filter.example.com [])
>  by orange.example.com (Postfix) with ESMTP id 32DB520523
>                                  ^^^^^^^^^^

No need to worry. The $protocol setting just chooses the code section
which will be processing the request. The $protocol = 'smtp'
chooses a code section (Amavis::In::SMTP) which is capable of handling
server side of an ESMTP or a legacy SMTP protocol subset. As it happens,
the same code section also implements LMTP. There is no need to manually
distinguish ESMTP from SMTP, as one is just a subset of the other.

Note that RFC 5321 also only speaks of 'Simple Mail Transfer Protocol',
(SMTP Model, SMTP Terminology, SMTP Procedures, SMTP Specifications,
SMTP Commands, SMTP Replies). The 'ESMTP' is just one of the allowed
keywords in the 'with' field of a Time-stamp-line, enabling an
extended set of commands and options.


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