On Tue, Jan 05, 2021 at 03:45:54PM +0100, Martin Husemann wrote: > Using a single mail server and making it send and receive mails from/ > for various domains is trivial, and completely unrelated to TLS or > certificates.
This suggest there is no need of separate certificates for separate domains. I think that would address TLS side of it. The thread is having relatively less discussion on TLS, but more on the tactics the mail servers (particularly the dominant players) apply to control spam (or so they say) - one of which is that they check reverse dns map between your ip and email domain. And because of such check would such setup work (work in the sense of acceptance by mail servers at large and if possible reducing the chances of them marking it spam). -- Mayuresh