Migration from Qmail to MS Exchange 2013. How would you do it?

Question

Email

Hey!
there is old mail on Qmail (pop/imap). somewhere 1000 users, and 3tb of data.
and Windows AD is.
the task is to upgrade to MS Exchange 2013.
As I see the process:
1. Exchange is installed
2. Exchange is configured to receive mail
3. Qmail is configured to receive mail from exchange (is it possible?)
if possible, then this way Users will be able to continue working with the old settings until the end of the migration
4. migrating mailboxes using imapsync
5. reconfiguring clients to the new Exchange using GPO.
6.profit!
What could I be missing? what would you add?
maybe some utility?

Answer 1

Wrong order, because Through the GPO you will not reconfigure anything.
Correct procedure:
You specify your mail domain in Aix as "internal relay domain", in this case, if the mail address is not found in Aix itself - Aix will send mail to another mail server for this mail domain. Do the same for Qmail.
Take care that Ex knows where to send (where Qmail and vice versa) and redirect acceptance of incoming mail to Ex.
Further - simply, you process users in batches, create a PY, send mail from Qmail to Ex, set up Outlook for the user, delete him from Qmail'a (or at least change the mailing address).
Voila, you can migrate as much as you want, the only problem you will have is with distribution groups, but those are solved.