[MlMt] Customising From or Reply-To based on Smart Mailbox settings

[Bill Cole]

On 2026-02-13 at 20:14:50 UTC-0500 (Sat, 14 Feb 2026 14:14:50 +1300)
  <mailmate at lists.freron.com>
is rumored to have said:

> As I manage my own domain name I'm able to make-up mail addresses to 
> match the group or organisation I'm dealing with whenever I'm asked to 
> provide one.

I've been doing this for 30 years. It helps keep my "real" mailbox clean 
AND helps me organizing my email.

> Rather than creating a corresponding email account on my server (too 
> much effort) I simply create a Smart Mailbox in Mailmate which filters 
> on the TO address.
>
> Mail to these addresses all ends up in the postmaster account unless I 
> generate a forwarding rule. I usually reserve that action for 
> forwarding them to /dev/null when the organisation becomes annoying.

I think you may need to expand your server-side work...

> That works perfectly for receiving mail. However, when I reply to mail 
> the FROM field is postmaster@ rather than my whatever_lol@ 
> not-an-email address.
>
> I'd really like to have some way of auto populating the From or the 
> Reply-to field without having to remember to use the Customise option.
>
> Are there any hidden tricks in Mailmate that I can leverage to achieve 
> this?

Not sure if it's enough, but if there's a pattern to the addresses you 
use, and you know how to write "regular expression" patterns, use the 
"Address Pattern" field of the Edit Account dialog box to cover the 
addresses that *might* end up in a To header.

It will NOT work by itself with mailing lists, which put their own 
address into the To header. For that, you need to make your mail server 
add an "X-Original-To" header with the original envelope recipient 
address that was eventually dropped into the postmaster box. for 
example, all the mail in my MailMate List mailbox has this:

   X-Original-To: mmlist-20120120 at billmail.scconsult.com

And MailMate automatically used that address when I started this reply.

Your mail server MAY already add that header automatically. Postfix does 
it by default, based on the enable_original_recipient setting defaulting 
to "yes."

I take this all a step further, with my mail server delivering (via 
procmail) everything sent to any address other than the "real" one into 
some other mailbox, with newly created ones and those with low volume 
landing in a generic "Tagged" mailbox, in which replies still work 
right.



-- 
  Bill Cole
  bill at scconsult.com or billcole at apache.org
  (AKA @grumpybozo at toad.social and many *@billmail.scconsult.com 
addresses)
  Not Currently Available For Hire