Philippe Cerfon:
> Hi list.
>
> I was recently looking over my postfix config and RFC 5321 in order to
> see whether everything seems still to be compliant (not postfix,.. but
> my config ;) ).
>
> Then I stumbled accross the following:
> http://tools.ietf.org/html/rfc5321#section-4.1.4 says:
> A session that will contain mail transactions MUST first be
> initialized by the use of the EHLO command. An SMTP server SHOULD
> accept commands for non-mail transactions (e.g., VRFY or EXPN)
> without this initialization.
>
> However having smtpd_helo_required = yes (which is the non-default)
> ALWAYS requires the HELO/EHLO, not only for mail transactions.
> I wasn't able to find a way to get RFC compliant behavior ... ok the
> RFC just says "SHOULD" so stricly speaking, they way Postfix goes is
> stilly compliant.
>
> Is it somehow possible to fulfil this SHOULD, whil still fulfiling the MUST?
With "smtpd_helo_required = yes", the Postfix SMTP server requires
HELO (or EHLO) before the MAIL, ETRN and AUTH commands (*).
If you disagree, then you MUST show the evidence that Postfix
behaves otherwise.
Wietse
(*) I SHOULD probably add STARTTLS to this list. An SMTP client is
not supposed to send ETRN, AUTH or STARTTLS without checking
first that the SMTP server actually supports the feature.
