I use my personal mail server for mails that go out of my app (transactional emails only), and for employees company mail inbox. Now I would like to send out some newsletter for the first time in bulk numbers (to my existing customers of course, yes GDPR :)). I would like to use one of services for that (mailgun, mandrill, etc, - havent decided yet). Is it possible to use same domain for both private mail server and for external service to send mails on your behalf, without having to sacrifice private server DNS settings?
Decision explanation:
My private server is doing a great job, getting the top scores with anti spam services, but i want to keep it small, dont want to take my chances ruining my spam reputation making some mistakes when playing with big numbers.