Replacing Amavisd with Rspamd in ISPConfig 3.1 on Debian and Ubuntu
Rspamd is a modern high-performance spam scan software for Linux servers which delivers very accurate filter results. This tutorial describes the steps to replace amavis (amavisd-new) spam scanning software with Rspamd on an ISPConfig 3.1 server.
Source: Howtoforge Linux Howtos und Tutorials