• Schneier
• Krebs
• The Hacker News
• EFF
• (ISC)^2

Sendmail + Mimedefang + Spamassassin + Dovecot + Sieve

For calendar and contacts I’m using radicale.

Authentication is via ldap.

This solution admittedly requires a bit of experience and knowledge of how it all works. It blows the doors off most bundled or commercial things you’ll find though.

I host my own.

As with all things infosec (and life in general), best practice is to not get yourself into the mess in the first place vs. trying to clean up the mess later. You should have already not had personal data “in the cloud” and should have been using unique identifiers and authentication for every service that you use.