Best practices: Sending email on behalf of users

Question

The company I work for provides testing services for the healthcare industry. As part of our services, we need to send email to our clients\' employees. Typically, these are t

Answer 1

You want to cheat and hack email authentication systems by trying to send emails on behalf of others. Maybe this hack can work temporarily, but in the future it will be banned by mailbox providers, as phishing attacks require more and more strict policies mailbox providers need to apply.

To avoid such hacks here is a solution I would suggest. Create a unique email address for every client and make it "mediator" for conversation between client and employees.

How it works

All email conversation must be done through your created email. You can set custom display names (e.g. John <123@yourdomain.com) to not confuse email receivers with your strange unique ids. So when A needs to write to B, it actually writes to your email, then you forward email to B, and vice versa for B to A.

This implementation have some complexity, but that will be paid in the future.