What I am trying to do is create a ‘reverse alias’ (next to an alias). The
alias must be used when mail is sent to a specific domain.
> On 1 Feb 2021, at 17:59, Gerben Wierda <gerben.wie...@rna.nl> wrote:
>
> master.cf gets:
>
> mycanon unix - - y - - smtp
> -o smtp_generic_maps=$mycanon_generic_maps
> smtp unix - - y - - smtp
>
> /opt/local/etc/postfix/transport gets an extra line:
>
> example.com mycanon:
>
> main.cf gets:
> mycanon_generic_maps = inline:{ { @mydomain.net = myal...@mydomain.net
> } }
Now, I’ve tried this for a couple of receiving domains
in transport:
gmail.com mycanon:
myn...@icloud.com mycanon:
Both gmail and icloud receive mail from myal...@mydomain.net
<mailto:myal...@mydomain.net>, so it seems to work. However, with an Office 365
hosted domain, something goes wrong
transport:
someoffi365domain.com mycanon:
delivers a message without a changed sender
transport:
specificu...@someoffi365domain.com mycanon:
does not deliver at all to the final destination, but it is successfully
delivered to the MTA from outlook.com (then disappears).
What I suspect here is that DKIM is the problem. As trivial-rewrite changes the
message, the DKIM signature is no longer valid. @gmail.com reports the fail
(spf is OK) but delivers anyway. Office365 is more strict it seems.
So it works, but it breaks DKIM, because DKIM happens before the rewrite?
So, suppose I want to do a sender rewrite that survives the DKIM generation?
(I’m using rspamd for that). Probably solve this in Rspamd, right?
Gerben Wierda (LinkedIn <https://www.linkedin.com/in/gerbenwierda>)
R&A Enterprise Architecture <https://ea.rna.nl/> (main site)
Book: Chess and the Art of Enterprise Architecture <https://ea.rna.nl/the-book/>
Book: Mastering ArchiMate <https://ea.rna.nl/the-book-edition-iii/>
