sender rewriting scheme

[Mathieu Gosset]

Thank you

Afaik SRS involves modifying the envelope, and set the return-path to an
address that will pass SPF validation, though in order for possible bounces
to arrive to the original sender, the address contained within the original
return-path is encoded into the new address (and translated back if a bounce
occurs). This can be done at the MTA level for postfix with e.g postsrsd but
that's usually domain-level forwards (i.e all mails for domain A are
forwarded to domain B).
It would have been convenient if there were a way to do that with dovecot so
as to have SRS compliant redirects (if a particular user wants all his email
temporarily redirected to gmail for example).
The problem I guess is it can't be just be implemented at the sieve level:
even if the envelope could be modified from sieve (which I'm not sure it
can, the envelope plugin just provides way to read the envelope), the
rewritten address wouldn't be recognized by the MTA when a bounce occurs,
the MTA as to be SRS aware anyway. 
One workaround I can think of would be to use a specific domain (or sub
domain) for the rewritten addresses, and a catch-all account with a sieve
rule that would check if it's a valid SRS address and translate it back so
as to reinject the bounce to the MTA queue so that it reaches the original
sender. I'm probably overlooking some possible problems with that though

-----Message d'origine-----
De : Matt Pallissard [mailto:matt at pallissard.net] 
Envoyé : vendredi 1 mai 2020 15:29
À : Mathieu Gosset
Cc : dovecot at dovecot.org
Objet : Re: sender rewriting scheme

Isn't SRS just mucking around with the headers?


If you're doing this globally, you'll likely want to handle it at the MTA.


However, if you'd like individual users to be able to set it up on their
own, you can probably handle that in sieve.  Sieve supports modifying the
headers.

https://doc.dovecot.org/configuration_manual/sieve/configuring_auto_forward_
sender_address/



Someone else on this list may know better than I.


Matt Pallissard


On 2020-04-30T17:50:37 +0200, Mathieu Gosset wrote:
> Hello,
>
>
>
> I would like to know if dovecot/pigeonhole provide a way to do sieve 
> redirection with sender rewriting scheme (srs)?
>
> I apologize in advance if that e-mail address isn't meant for 
> assistance, but  I've asked on the official irc channel on freenode 
> and was told to direct my query to dovecot at dovecot.org, I hope you won't
mind.
>
> Thanking you in advance
>
>
>
> Best Regards
>
>
>
> Mathieu Gosset