BUG: proxmox mail gateway FROM = null bypass spam filtering

[herezy]

Good day,

I have been having 2 issues. 1. When an email is received with a null from field it bypasses all the spam filtering. As well It does not show up in the Tracking Center at all.

026-05-29T12:57:03.346227-04:00 mail postfix/qmgr[1131]: 4716E20023: from=<>, size=6429, nrcpt=1 (queue active)
2026-05-29T12:57:03.346359-04:00 mail pmg-smtp-filter[1141]: 2013B6A19C55F43565: accept mail to <info@DOMAIN.NET> (4716E20023) (rule: default-accept)
2026-05-29T12:57:03.349266-04:00 mail postfix/smtpd[2085]: proxy-accept: END-OF-MESSAGE: 250 2.5.0 OK (2013B6A19C55F43565); from=<> to=<info@domain.net> proto=ESMTP helo=<[10.88.0.3]>

I had been troubleshooting a way around this issue with Claude.ai without success.

update: work around on the mail server to block any emails that Return-Path' header matches the following patterns: '<>'. At the moment I have it set to send it to me for approval incase its a legit email.

 

[herezy]

Any plans or fixes on the pmg side to block these bozos?

 

[Stoiko Ivanov]

1. When an email is received with a null from field it bypasses all the spam filtering.

this is not the case in general - it depends on your active rules (you need a rule with a Spam Level What object (and Block/Quarantine as Action) in the direction of the mail - which rules are active in your setup?

. As well It does not show up in the Tracking Center at all.

You need to enable the 'Include Empty Senders' checkbox

Please share your rules and the complete log of the mail (some lines are missing here)

Additionally - please check-out the getting started guide in our wiki - it contains a few helpful pointers to get started:
https://pmg.proxmox.com/wiki/Getting_started_with_Proxmox_Mail_Gateway


I hope this helps!