RSPAMD integration for Domino?
Daniel Nashed – 16 December 2025 18:57:12
My mom just asked me about a e-mail she got because she did not order anything online.I got those type of messages for a while because spammers got more clever the last years.
Even with DKIM and SPF enabled, gray listing and some other rules in my SpamGeek application I still get spam.
So here is the new before x-mas project. I looked what open source solutions would fit well for Domino. This might also be a good option to add Antivirus to my SMTP gateway.
https://rspamd.com/
RSPAMD looks great as a plug-in into my existing SpamGeek to provide additional score.
It also has interesting extensibility and comes with a couple of interesting data pools to build rules with.
There is also a new integration for OpenAI and Ollama - which I want to look into once I got it integrated.
It also has options it integrate ClamAV and other virus scanners. Which are also on my list to look into after it is integrated.
The first idea to integrate it was to use the milter interface which I have already implemented as a client lib in C earlier.
But RSPAMD has another interesting option. They have a REST API which provides more input and result options.
You can add metadata like IP, helo and sender etc via HTTP headers and get JSON with a detailed score back.
RSPAMD also speaks HTTP over UNIX socket in addition to TCP/IP.
So I implemented C/C++ code to post the EML with the metadata, get the result back in JSON format and parse it.
Because the integration will later need to work with the MIME stream I read from a document step by step I also implemented HTTP chunked transfers to not have to read the full file into memory first to know the content length.
This looks very promising and I will do some testing with existing data first.
Porting it to Windows would make it more complicated because the API differences.
If I would, introducing OpenSSL as the network layer would make sense to avoid Windows vs. Linux TCP/IP operations.
Linux is just so much more straightforward and flexible. Using a UNIX socket makes it more elegant.
Is anyone using RSPAMD already?
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1Hunter-NL 17.12.2025 14:31:50 RSPAMD integration for Domino?
Yes, We using it for a long time already. We used it with postfix as an inbound/outbound mail gateway in front of our Domino domains. I'm also investigating to integrate it more into Domino, so users can easily "mark" messages as spam/ham, so RSPAMD can learn from it (bayes/fuzzy). I'm trying to do this as a domino extension. Acting on "add/move/delete" event of the junk folder, so it can also being used by Traveler, IMAP clients and interact with RSPAMD to learn from it.
The RSPAMD metadata exporter stores all raw mail data into our PostgreSQL server database and keep it for a few months. So RSPAMD can use the raw original mail message to learn from it. Providing Domino version of the mail (in EML) results into more incorrectly learning. It is just not the same as the original raw message.
Recently RSPAMD also introduced categories to bayes and HTML fuzzy processing. Then users can even more specific marking the messages to be for example PHISHING, Marketing, etc. Currently we categories it with use of the RSPAMD GPT plugin. With different scores for each category, it helps a lot to improve filtering the bad stuff.
2Daniel Nashed 17.12.2025 22:35:09 RSPAMD integration for Domino?
@Hunter-NL,
Thanks for your great feedback. I sent you a longer mail.
The integration with hooking into Junk folder is a good idea. But really challenging to integrate.
There is an extension manager event when mails are added to a folder. but not when they are removed from a folder.
The extension manager would also need to check the user and process doing that.
Also this extension manager would need to be on all of the servers where user modifications of folder data can happen.
I would not see another way that would work cross devices and EMs are the very very low way to get triggered by events.
-- Daniel
3Thomas Bahn 22.12.2025 20:06:53 RSPAMD integration for Domino?
Hi Daniel,
we have been using Rspamd alongside CipherMail (for encryption) and Postfix as the MTA for quite a few years now.
Ciao
Thomas