Small mail server best current practices
Running an email server became a real pain about 4 years ago. Until then, we could run our own exchange server, control everything and it was awesome. Then came the email security products from the large companies.It became a self fulfilling prophecy. Our email would trigger a rule in big co's third party security app, which would then report to a centralized rule breaker clearing house automatically. Clients couldn't receive our emails, we would dive in, submit appeal to clearing house, get clear and a week later do it all again.Everything was configured properly on our end. We passed all the online validation engines. IPs were our own personally owned block and pristine.It became too much.Switched to office365 and all problems magically disappeared. Sent emails to same big cos with third party email security and haven't had a single issue.