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.<p>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.<p>Everything was configured properly on our end. We passed all the online validation engines. IPs were our own personally owned block and pristine.<p>It became too much.<p>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.