[Alpine-info] email+TAG@domain

[Andrew C Aitchison via Alpine-info]

On Sun, 21 Sep 2025, via Alpine-info wrote:


>>> A possible workaround might be to add a similar option that matches on 

>>> Delivered-To: headers, applies a sed(1)-style transform, and copies the 

>>> result to the From: field.

>

>> Is there any other header besides Delivered-To that has the information you 

>> need? My information is that this header is defined in an experimental RFC 

>> from about 3 years ago, but I do not find it in the headers of the message 

>> I am replying to, so it has not been widely adopted yet.

>

> Huh.  It's been in both qmail and Postfix for more than twenty years; and 

> it's been in Gmail since launch.

>

> It also seems to be a well-known, standard answer to this kind of problem. 

> There are plenty of Stack Exchange, etc, answers that mention it, going back 

> for at least fifteen years.  See, e.g., 

> https://webapps.stackexchange.com/questions/5719/is-it-possible-to-create-a-gmail-filter-that-works-on-headers-other-than-from-t

>

> I had assumed it was universal.  :(


Neither Delivered-To nor X-Delivered-To are in the Exim source but the
test configs contain examples of each, so it is possible with Exim,
but not enabled by default in the default config.


> As far as I know, there isn't another usable header; and certainly not one 

> that's more widely deployed than Delivered-To.


The draft RFC
   https://www.ietf.org/archive/id/draft-duklev-deliveredto-00.html
suggests that Delivered-To does not need to match the
sender address, nor the envelope sender. It is merely
   an MDA-specific representation of the mailbox
   to which a message was delivered.

It says that some MTAs store the "RCPT TO" address in a Envelope-To or 
X-Original-To header.

-- 
Andrew C. Aitchison                      Kendal, UK
                    andrew at aitchison.me.uk