I recently answered a few questions here on this topic. It seems that most people are not aware of it, but this is the intended behavior.
All emails go through the entire SA filter chain. At the end of this chain, the action object is executed. If a sender is listed under Mail Filter → Who Object in either the blocklist or the welcomelist, it will take effect—but only after the entire SA filter chain has been processed.
If you want to block the email earlier, this must already happen in Postfix, for example in /etc/postfix/senderaccess.
Drawback: if you manually add entries there, Proxmox will regularly overwrite them, because this list is managed via PMG under Mail Proxy → Welcomelist.
However, it is only possible to add positive entries ("OK") there, not negative entries ("reject").
This bothered me as well, so I wrote my own policy service (“policyguard”) that handles these tasks in Postfix for me. There you can define your own blocklists or regex rules, which can also block your domain, among other things.
From my side, the tool is mainly designed to deal with annoying Google junk, but I do actually maintain a few senders there manually as well.
Just add your TLD to the SENDER_BLOCK_INCLUDE:
Code:
SENDER_BLOCK_INCLUDE = ["firebaseapp.com", "ru" ]
Google operates several services that are commonly abused for sending spam. The following sections describe each service and the filtering strategies used.
Firebasemail / Firebaseapp
Firebase is a Google-hosted platform that is frequently exploited for sending unsolicited email.
- Emails sent directly through Firebase use the domain firebaseapp.com and can be blocked by sender domain.
- Some senders use Firebase with their own custom domains, making direct domain blocking ineffective. However, these senders can still be identified early: their domain's SPF record (DNS TXT)...
From my point of view, I don’t think much of blocking individual TLDs.
There are simply too many domains to maintain them in a huge regex list. Instead, do it the other way around and assign penalty scores to everything you don’t regularly expect mail from.
Additionally: use geoblocking—this targets the geographic region rather than the domain extension.
I wrote an exceptionally detailed article on this topic.
I've been intensively working with Proxmox MG over the past few days and found the documentation not always helpful.
My spam has been reduced by 95%, and I would like to explain here what I changed compared to the out-of-the-box installation to achieve this. From my perspective, this is something that is insufficiently covered in many guides.
Thanks to the Proxmox team for this excellent product and thanks to everyone whose comments and recommendations I implemented. Feel free to comment — if you like this post, leave a subscription and a like … just kidding.
My policy is to reject emails...