Is there a self hosted application I can set up with Postfix in order to track and record the delivery status and information of every single email sent out (e.g. subject, sender, recipient, opens, clicks, bounces and complaints)? So that I can have more control over the email server and avoid sending spam. I have an Ubuntu 16.04 server with ISPConfig 3.1.
Monitoring those would not prevent sending spam, you might be able to prevent sending more spam if you automatically disable sending when too much spam was sent. These you can see from mail log: subject, sender, recipient These you would have to monitor on the receiving e-mail server: opens, clicks, Bounces arrive at your mail server. Complaints may arrive, depends on where the complaints are sent. I do not remembe ever receiving complaints from spam sent by my server, I notice spam was sent when I find my mail server on some black list. You do not mention what operating system you have, but maybe pflogsum is available for your OS. Same goes for mailgraph, which draws graphics from mail server statistics so you spot if unusually large amounts of something is happening.
