Re: [exim] BATV configuration

On Wed, 4 Jun 2008, Ian Eiloart wrote:

> It'll work fine, but Exim's vacation messages are (incorrectly, IMV)
> sent to the From address not the sender address.

(without wishing to get too off-topic from BATV)

The traditional argument in favour of this mode of operation is that the
vacation system operates in lieu of a real user (who is absent), and
therefore it should reply in the same manner as the real user would
operating his MUA to reply to the original message; so it sends to the
From: address, or the Reply-To: address if the sender has specified it.

However, RFC 3834 was a (welcome) attempt to define behaviour of
autoresponders in different circumstances, and defines a vacation system
as a "Personal Responder". It specifically states that because of the
variability of the From: field (it may contain more than one address) and
other factors it should not be used, neither should Reply-To:, see section
4 for the discussion.

There have been various discussions on the list in the past about this;
some argued vociferously on this list that an autoresponder should operate
exactly as a human-operated MUA, and thus respect From: and Reply-To:,
however all generally agree that the return address on the auto-reply of
either the null sender, or a blackhole address, should be used to prevent
risk of message loops (which of course isn't exactly as a human-operated
MUA operates).

It is a while since I looked at what Exim did, but as I recall there were
two main ways of generating an auto-reply. One was using the "vacation"
command in a filter, whch by default uses $reply_address (== "From:", or
"Reply-To"). The other is the autoreply transport, which takes a "to"
option which has no default, so leaves it up to the user to make the
choice of address to use.

FWIW, I err on the side of using the SMTP sender address too, from the
autoreply transport and specifying:

# Errors-To: is deprecated
# There are arguments over whether this should send to the SMTP sender, or
# to a From:, Reply-To: or Resent-From: header
to = "${if def:h_Errors-To: {$h_Errors-To:} {$sender_address}}"

Jethro.

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Jethro R Binks
Computing Officer, IT Services
University Of Strathclyde, Glasgow, UK