Hey there - thanks for your guide! I used it as a base for my own guide but tweaked for Slackware64 14.1 (https://gerardozamudio.mx/2015/04/25/slackware-mail-server-w...). I'm in the process of updating it for the upcoming Slackware 14.2 release. I'd love to get your feedback on it if you ever have some spare time.