I wrote on the subject some years ago:
http://yalis.fr/cms/index.php/post/2014/01/31/Why-buy-a-domain-name-Secure-mail.
This may interest you.
I am in the process of setting up a newer configuration, all with Ansible,
among which are Exim and Dovecot, with real users and virtual users, and
with delivery by LMTP, all based on information stored in LDAP. But I
cannot promise any "release date" since I do not have much time these
days...
Cheers
On Mon, 9 Apr 2018, Peter Hutchison via Exim-users wrote:
> Has anyone implemented any of the following on their mail systems? StartTLS, DMarc and DKim.
>
> I would just like to any tips, gotchas, downsides or other useful information I should know?
>
> Peter Hutchison MCP
> Senior Network Systems Specialist
> * 01484 473716
> Networks Team
> University of Huddersfield | Queensgate | Huddersfield | HD1 3DH