Question Migration from Plesk Email Security (Amavis, SpamAssassin 3.x) to Rspamd 3.12 – Experiences?

[Jürgen_T]

Server operating system version

Ubuntu 22.04.5 LTS

Plesk version and microupdate number

Plesk Obsidian 18.0.70

Hi everyone,
I'm planning to switch from the default Plesk Email Security stack (Amavis, SpamAssassin 3.x, Pyzor, Razor, etc.) to a more modern and efficient solution based on Rspamd 3.12 on my Ubuntu 22.04 server.

The decision comes mainly due to:

• a massive increase in spam recently, with more sophisticated techniques slipping past traditional filters, the lack of support for SpamAssassin 4.0.1 in Plesk Email Security (PES), which means we're stuck with an outdated and less effective version and the need for better performance, more transparency, and better integration with modern standards like DMARC, ARC, and neural scoring
  My current system:

• Plesk Obsidian v18.0.70
• Ubuntu 22.04.5 LTS
• Postfix + Dovecot
• Dedicated server with 32 GB RAM
• Manual integration of ClamAV and custom SpamAssassin rules in 50-user
• 
  
• I’ve set up Rspamd with ClamAV and DKIM/DMARC support as a native installation (not via Docker), and initial tests are promising. However, before fully decommissioning Amavis and SpamAssassin, I’d love to hear from others who've already done this.

Key questions:

1. Have you fully replaced Amavis + SpamAssassin with Rspamd under Plesk?
2. Any issues or caveats with Plesk's mail stack or control panel?
3. How stable is Rspamd in long-term production use with Plesk?
4. How do you manage spam learning and quarantine outside the PES UI?
5. Any recommendations for Rspamd performance tuning (e.g. with Redis or multithreading)?

I’d really appreciate your feedback and insights – especially if you’ve tackled similar challenges. Thanks in advance!


Best regards,
Jürgen

 

[Kaspar]

I don't have any experience with using Rspamd on a Plesk server. I don't think there should any issue using it with Plesk, but there is just no way to mange it from within Plesk (unless you create your own Plesk extension to do so).

I have used Rspamd in the past on other servers (just not with Plesk). I've never been really impressed with it's spam recognizing abilities. From what I remember it's more efficient (uses less server resources) and does a better job out of the box in recognizing spam compared to spamassassin. Rspamd has a pretty active community as well, which is nice. However I've found that there are many more options and plugins for spamassassin to tweak spamassassin which make spamassassin more powerfull and can outperformed Rspamd.

It might be different now, it's been a couple of years since I last used Rspamd. I've never bothered to use Rspamd again since spamassassin does a pretty good job for me (but I heavily customized my spamassassin setup).

 

[Jürgen_T]

Thanks for your input – much appreciated!


I totally agree with you: SpamAssassin can be extremely powerful when heavily customized. I’ve also maintained a fairly extensive setup over the years with custom rules in 50-user, Razor, Pyzor, DNSBL tuning, and even DKIM/ARC scoring workarounds. So yes – with enough tweaking, SA can really shine.

That said, my motivation to test Rspamd 3.12 stems from:

• the rising volume and sophistication of current spam attacks
• SA 4.0.1 not being available in Plesk Email Security
• and the need for better performance, faster processing, and modern scoring features (neural, ARC, etc.)

I’ve now implemented a full native (non-Docker) Rspamd setup with:

• Redis for Bayesian learning
• ClamAV integration
• DKIM/DMARC/ARC validation
• GeoIP-based scoring (e.g. country-specific weights)
• and custom rules with symbol reweighting for specific IP ranges and ASNs.

The results so far look promising, but I’m still fine-tuning the thresholds and learning behavior. I’ll be happy to share the results here after a few thousand messages have been processed – particularly regarding false positives and overall spam recognition.

Thanks again – it’s great to hear from someone who’s worked both sides of the fence.


Best regards,
Jürgen