Weekend well spent: configuring Postfix Dovecot DMARC DKIM on Debian Trixie (13.1).
Everything’s been rewritten. Dovecot 2.4 dropped mail_driver / mail_path, Postfix 3.10 broke half the guides written a decade ago, and DMARC reports hit INBOX but vanish in IMAP thanks to the
@nonexistent home-dir bug.
Every tutorial still says “add home_mailbox = Maildir/” — which bypasses LMTP and dumps to mbox. “Set virtual_alias_maps!” — bounces with
@localhost. “Remove mydestination!” — still bounces. “Add virtual_mailbox_domains!” — Mail Delivery Status Report will be mailed to <root>.
AI advice? Like giving a kid a knife and saying make bread.
It repeats the same fix that already failed, then blames SPF. (Spoiler: SPF is for sending, not receiving.)
Meanwhile AppArmor makes root mortal, Gmail defers with 421-4.7.28 UnsolicitedRateLimitError, and every “expert” blog is frozen in 2014.
After seven hours, sixty reloads, fifteen postmaps, and more coffee than sense, the magic combo was:
remove
$mydomain from mydestination
virtual_mailbox_domains =
mycompany.fi,
mycompany.net
postmap virtual
reload
Finally: “deliverable: vladputputin@localhost” — and mail lands in Maildir.
Lesson learned: if you’re setting up mail on Linux in 2025, skip the AI, ignore the blogs. Read man postfix and doveconf, test with sendmail -bv, and embrace the pain. Debian Trixie is the T-1000 of mail servers — it keeps morphing, but it never gives up. 🦾
#Linux #Postfix #Dovecot #DMARC #DKIM #DebianTrixie #SysadminLife #EmailAdmin #TechFrustration