[Dovecot] Dovecot LMTP does not pass envelope recipient +detail to sieve

[Greg Rivers]

On Mon, 6 Jan 2014, I wrote:

> I found this[1] thread that describes the same problem with dovecot-LDA, 
> but the solution (add X-Original-To: header) has no effect with LMTP.
>
> My sendmail LMTP configuration:
> FEATURE(`local_lmtp',`[IPC]',`FILE /var/run/dovecot/lmtp')
>
> Sendmail's address test indicates that sendmail is providing user+detail 
> to LMTP (see below).  Except for this problem, dovecot, LMTP, and sieve 
> are all working perfectly.  Is there something I'm missing, or is this a 
> bug?
>
> [1] http://dovecot.org/pipermail/dovecot/2012-July/136987.htm
>

It seems I was mistaken.  By tracing the LMTP session between dovecot and 
sendmail I found that sendmail does _not_ include the +detail in RCPT TO:. 
I also determined that dovecot LMTP will in fact extract the +detail from 
a X-Original-To: header, but only if one defines 
lda_original_recipient_header.

So for the archives, to get sieve's "envelope :detail ..." working with 
sendmail and dovecot LMTP, do the following:

1) Add "lda_original_recipient_header = X-Original-To" to 15-lda.conf

2) Add the following rule to sendmail.mc to add a X-Original-To: header 
to every message:

LOCAL_CONFIG
H?${u}?X-Original-To: $u

-- 
Greg Rivers