I was 3 hours ghost hunting an issue, which just did nost exists....
#TIL: postfix' /var/lib/postfix/verify_cache.db - here are map lookups cached (e.g. you use transportmaps stored in mysql). Also the ones, when a user wasnt found. -.-
550 user does not exists your a$$ !
After a night playing around with #modoboa I think I found my next mailserver solution. It's easy to install, looks also easy to maintain, written in python, comes with important core elements, but no bloated stuff, works quite nice in my testing environment :)
#mailserver #selfhosting #mail #admin #mailadmin #postmaster
OK. After my rant about sendgrid servers sending me a lot of phishing mails (mostly Trezor related), I actually checked on how to report abuse to them and it turns out that they listen and care. Just forward the email with all original headers intact to their abuse mail address and after a sanity check they will accept the complaint, open a ticket and go after their customer doing this shit. Chapeau.
I am THIS close to fully blocking all IP ranges from AS11377 (Sendgrid) on my mailserver as the only thing they are sending my way is Trezor phishing mails. Fellow #postmaster #mailAdmin how do you treat them?
#NerdTalk Wow. A multi-step, sophisticated way of spoofing emails that pass SPF, DKIM, DMARC. Hardcore.
"And most importantly, the key trick is that you can put anything you want in the App Name field in Google"
Le sigh. That's where they put the email text. In the App Name field. Google can fix this by sanitising input better.
https://easydmarc.com/blog/google-spoofed-via-dkim-replay-attack-a-technical-breakdown/
```
if address :match "From" "*@gmail.com" {
fileinto "SPAM";
}
```
Current frustration level of being a #mailadmin over 900000.
These days is there even a single legitimate user sending mails with an gmail.com address? Literally all of them within my inbox are spam...
because running a mail server wasn’t fun enough: the Dovecot 2.3 → 2.4 update has tons of breaking config changes
(h/t to https://willem.com/blog/2025-06-04_breaking-changes/ for the exhaustive breakdown of the changes)
For the first time ever, I've got spam.
It's from 102.213.93.28 (AfriNIC) and there is no abuse mail in the whois output, only telephone numbers. What should I do? I can DM you the full headers/mail, if it helps.
#spam #SpamMails #spammail #mailserver #mailadmin #mailadmins #afrinic #whois
#tfw You have to email a government agency, explain in excruciating detail why your mail server (and any other that enforces #DMARC) can't receive certain emails they're sending that fail their DMARC policy, and then cross your fingers and pray that the tier 1 customer service rep who reads your email forwards it to someone who can fix the problem AND said someone actually takes the time to do it. *sigh*
#smtp #SysAdmin #MailAdmin
