On Wed, Aug 06, 2014 at 03:00:43PM +0000, Xie, Wei wrote:
> You are totally correct. Our previous email system was running
> like yours - forwarding accounts' mail flow to externally hosted
> users is separated from real outbound mail flow that our internally
> hosted users send out. Current Microsoft exchange system can't
> archive this goal. As you know, when politics involves business
> and technical decision, many reasonable things in the past have to
> be changed.
This is simply not the case. Exchange supports per-domain
"connectors", that can send mail for selected domains to
dedicated relays. In my design Exchange forwarded hosted
recipients (a matter of populating the forwarding addresses
that way) to a sythentic internal domain:
user@<providername>.example.com
where "example.com" was the primary internal domain. This
domain was routed to dedicated Postfix outbound relays, which
in turn performed rewriting of these addresses to the actual
mailbox address at the provider.
There are many ways to skin this cat.
--
Viktor.
