I am doing work for a manufacturer. They have email that is hosted by the ISP, so it is not in house.
I have a legacy system (AS400/iseries) that is in-house that I am sending emails out to vendors for Purchase orders. The system creates PDF's then creates the email and sends out. So it does not go thru the regular email system.
So, we have had some emails not get delivered and some bounce back. I have gone thru the option to tell Office 365 to whitelist the ip address we are sending from.
The question is, Can we tell the world that our IP is safe via DNS in some way? Otherwise, we are going to have to send emails to companies that we get kickbacks from and request that they white list us. Issue is small now, but I am getting ready to add customer service to emailing invoices, etc too and it is only going to get bigger.