So in a previous blog post I set up postfix and dovecot by sort of following an online guide. Well the author of that guide has updated it for debian stretch. This doesn't help me much, as I already built my mail servers on debian stretch by adapting his previous guide. But some of the changes do interest me. I have been meaning to set up DKIM and DMARC, and the new guide includes instructions on doing so. The new guide also includes instructions for setting up clamav, which wouldn't hurt. However the instructions for clamav depend on using a new anti-spam tool, and I am actually getting on with spamassassin, on top of this the new anti-spam tool is not in the debian default repositories, which puts me off somewhat. They do provide an APT repository for stretch though which eases this concern a little. The new tool also supports some features I may be interested in, including greylisting shared across hosts by using redis (a piece of software I may be a little familiar with) a possibility that intrigues me. I am going to read this new guide, and decide if there is anything I wish to take from it, if so I shall almost certainly write a new blog post on the matter, if not I probably won't.