Hey Ionel It is great to hear that you like OpenSMTPD! I currently use zimbra for a very small home mailserver setup and I also plan to move to OpenSMTPD. I have not noticed any spam problems yet, but I have a different problem with zimbra - it is a resource devouring java monster..
Take a look at [ https://github.com/poolpOrg/filter-rspamd, | https://github.com/poolpOrg/filter-rspamd, ] It is written in Go, and this is the filter that Gilles uses for rspamd. Ihor From: "GARDAIS Ionel" <ionel.gard...@tech-advantage.com> To: email@example.com Sent: Tuesday, December 3, 2019 11:26:44 AM Subject: Filter API and protocol Hi list, I've installed OpenSMTPD on a fresh OpenBSD to act as a simple-yet-powerful MX for inbound trafic. Our current zimbra mono-server installation is quite bad at spam detection thus I gave a try to rspamd. First results are encouraging and I really appreciate the ease of configuration of OpenSMTPD and the clarity of its logs. I'd like to add a feature to our setup : prefixing all incoming emails' subject with a string, only once (i.e. not if the said string is already in the subject). It seems to me that this should be made as a filter in OpenSMTPD, with a low-precedence to be placed after DKIM verification. I'd like to give a try at this solution. Do you have pointers to the filter protocol or to an hello-world filter ? Thanks,