Harder than people expect.
WHAT IT INVOLVES
A mail server Spam filtering
Authentication: SPF, DKIM, DMARC
Reverse DNS Reputation management Storage and backups
WHY IT IS DIFFICULT
Deliverability. A new server's address has no sending reputation, and mail is treated with suspicion.
Major providers reject or filter mail from unknown sources readily.
WHAT THIS MEANS
Your mail may not arrive, and you may not know.
WHAT IS REQUIRED TO SEND RELIABLY
Correct reverse DNS SPF, DKIM and DMARC configured properly A clean address not previously used for spam Time to build reputation
THE HONEST ADVICE
For most people, do not run your own mail server.
Use hosting-provided mail, or a dedicated mail service.
WHEN IT IS WARRANTED
Specific requirements, or volume that makes it economic.
IF YOU DO
Monitor deliverability actively. Test to several major providers regularly.
