I'm hosting all my users websites on server1, it has multiple websites, e.g. user1.com, user2.com, user3.com ...
Our upstream provider no longer support reverse DNS, so I need to use server2 to help send out emails. Both server1 and server2 have Postfix installed.
I'd like to ask how to configure postfix and DNS of the users' websites so that server2 can send emails for all websites that are being hosted on server1, while these websites should still receive incoming emails normally to server1?
I have searched a lot but haven't found any relevant tutorial, so it is really great if anyone here can direct me to a good tutorial that I can follow.
Thank you!
