Let’s have another snippet of Run Your Own Mail Server.

Text file configuration works great for settings that rarely change. If your mail server is truly only for you, then text files will probably be fine. When you have a larger number of users or a more dynamic environment, however, you need easier management. That means a database. And a front end to manage that database, because routinely running raw SQL commands would require memorizing the database structure and that would consume brain space better utilized for something else. Anything else.

Many folks have written database-driven Postfix management systems. Some of them are even adequate. This book will use PostfixAdmin (https://postfixadmin.github.io/postfixadmin/), but primarily to illustrate database-backed Postfix and Dovecot. We won’t go through the web interface, because web interfaces frequently change and once you’ve managed Postfix via text files your most common question is “where did they hide the option for this setting?”

Running your own mail server requires sysadmin expertise. You should probably read some of my other books before trying it.

Here’s a few words about system upgrades–or, rather, a few words about about system upgrades.

Modern systems administrators have outsourced their memory to online forums and search engines, which worked until illiterate large language models got rebranded as AI and the resulting feral autocomplete engines stuffed your external brain’s technology section with reconstituted search-engine-optimized Scorpion fan fiction. Fortunately for you, so did your boss. You have the option to fall back on the computer’s built-in manual, whereas your boss thinks books like The Seven Highly Effective Cheese Mover Habits contains undying management wisdoms. He doesn’t remember anything from that either, but he keeps it on the back of the loo to present an image to anyone foolish enough to enter his lair. No, don’t touch it, the cheap paper those things are printed on absorb ambience and I should know. But did you consider, possibly, for a moment, working on the legitimate issue underlying your question? No you did not, as evidenced by the fact that whatever circuitous “reasoning” process that led you to write and send this letter betrayed you by permitting you to, once again, touch not just a computer but the Internet.

If this amuses you, check out my collection Letters to ed(1).

Here’s a few words on the Sender Policy Framework, aka SPF, aka omg why please no no no.

SPF is often touted as an anti-spam measure. It isn’t. It’s one component of a spam assessment policy. Competent spammers are among the most reliable publishers of SPF records, gleefully declaring that any host may send mail for their domains. Emails from domains without SPF records are likely to be classified as spam, however.

When a MTA with basic spam protections receives an email, it performs an SPF check against the sender in the envelope. This is the email address used in the SMTP exchange’s MAIL FROM statement, not the sender address that the recipient’s client shows. This check passes or fails.

SPF checks are also performed against the visible From address. If the domains match, the message is said to be in SPF alignment. Alignment is important for DMARC, so it’s best to configure alignment from the beginning.

This week’s work has a lot of formatting, what with sample DNS records and defining variables and such. If you’re interested in running email, or in making running your own email more accessible, you could sponsor this book.

Today I’m reading from a story that’s coming out this winter, “The Rats’ Man’s Lackey and the Forbidden Tinsel.”

I’d agreed to obey the rules. To walk away from my past, so that my demons couldn’t find me. This madhouse had no right to throw any of that in my face.

The thought calmed me.

Hiding in a root cellar while the opposition filled the house with bullets? The bad guys had no right to break their word. A teammate developed cancer? She’s the best person I know, this isn’t right! Any time I catch myself thinking about rights, I know I’ve derailed myself.

The only right we have is the right to die. Anything else, we claw out of the world.

I focused on my breath until I could think with more than my brainstem.

You got ding-dong ditched when your bellybutton still had a knotted cord attached—so freaking what? Your folks did what they thought best. Anything else would have been worse, and you came out okay. You had no right to this kind of Christmas, nobody gets this, and you’re too old to appreciate it properly anyway.

A couple of Rats’ Man’s Lackey tales are out already, with more coming soon.