SPF DKIM DMARC TLS Linux · Postfix · Email

Your emails are going
to spam.
Here's the fix.

A step-by-step guide to securing your Postfix mail server with SPF, DKIM, DMARC, and TLS — so your emails land in the inbox, every time.

mail-tester.com
$ dig TXT example.com +short
# Before reading this book
; no SPF record found
; DKIM: no key published
; DMARC: no policy
$ dig TXT example.com +short
# After
"v=spf1 ip4:1.2.3.4 -all"
"v=DKIM1; k=rsa; p=MIIBIjAN..."
"v=DMARC1; p=reject; rua=mailto:..."
✓ mail-tester.com score: 10 / 10

NAME YOUR PRICE

$

PDF + EPUB · 65 pages · Instant download · Pay what feels right (min $11.99)

WHAT'S INSIDE

7 chapters. Zero fluff.

CH 01
How email works
The mental model that makes everything else click. MTA, MX records, SMTP — explained without the jargon.
CH 02
Installing Postfix
A clean, minimal configuration from scratch. You'll send your first test email by the end of this chapter.
CH 03
SPF
Publish the DNS record that tells the world which servers are authorised to send mail for your domain.
CH 04
DKIM
Cryptographically sign every outgoing message with OpenDKIM. Step-by-step key generation and integration.
CH 05
DMARC
Tie SPF and DKIM together. Includes the phased rollout: p=none → quarantine → reject.
CH 06
TLS
Encrypt every connection with a free Let's Encrypt certificate. Auto-renewal, port 587, OpenSSL testing.
CH 07
Final checks & maintenance
A 12-point pre-launch checklist, mail-tester.com walkthrough, blacklist checking, log reading, and a monthly maintenance calendar.

THIS IS FOR YOU IF

You've set up a VPS and want to run your own mail server
Your emails keep landing in spam and you don't know why
You're comfortable with the Linux command line
You want to understand email security, not just copy-paste config

YOU'LL NEED

A VPS with a public IP address
A domain name with DNS access
Ubuntu 22.04 LTS or Debian 11/12
About 2–3 hours

BY SABLE QUINN

Stop guessing.
Start delivering.

65 pages. Real commands. Troubleshooting tables. Everything you need to get from broken to 10/10 on mail-tester.com.

NAME YOUR PRICE — minimum $11.99

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PDF + EPUB · Instant download · DRM-free