On Fri, May 27, 2022 at 07:55:31AM -0400, charlie derr wrote:
> Are there any suggestions on how we can make sure that both internally
> generated and external email reach both Gmail and Dovecot mailboxes
> without creating a routing loop?
Yes, you should gateway the "Bcc" email traffic from Gmail to a
dedicated SMTP service that delivers directly to Dovecot. This service
MUST NOT accept any other traffic (e.g. outbound mail from your users,
local mail notices, ...).
Which then makes it possible to route all other mail addressed to your
users from various internal systems, users submitting email, ... to
Gmail as the responsible mailbox provider.
In other words, delivery to "dovecot" is *always* after delivery to
Gmail, as a side-effect of the "Bcc".
> Our current idea is to rely on the existing Gmail dual delivery setup.
> We'd like to know if it's possible to configure Postfix on
> hedwig.simons-rock.edu so that:
> 1) Any email that originates on this system (or our roundcube webmail
> instance on warlock.simons-rock.edu) is first routed out to Gmail
> servers, even if the domain is simons-rock.edu and the user has a
> Dovecot mailbox.
> 2) Any email that is routed to (or back to) our internal servers via
> Gmail dual delivery (arriving via hormel.simons-rock.edu) is just
> delivered to a Dovecot mailbox.
Instead, use a dedicated SMTP service for the Gmail Bcc traffic that
is not intermixed with your own outbound traffic.
--
Viktor.
