Want to get rid of Google and have your private emails be really private? Building your own mail server is the solution.
If you just need to send monitoring emails from your server, consider the simpler guide to send emails.
Warning: Getting your own mail server is rewarding and fun, however it's harder and more time consuming than most sysadmin tasks like installing a webserver. If done incorrectly you risk loosing emails, being submerged by spams or being considered as spammer by others and not be able to send emails. That being said, I've been running my own mail server for almost a decade without any major issue.
To get a fully functional web server, you will need to go through these guides: