SMTP protocol basics from scratch in Go: receiving email from Gmail

from blog Notes on software development, | ↗ original
I've never run my own mail server before. Before today I had no clue how email worked under the hood other than the very few times I've set up mail clients. I've heard no few times how hard it is to send mail from a self-hosted server (because of spam filters). But how hard can it be to hook up DNS to my personal server and receive email to my...