Anything I (am able to) build myself.
Also, things that are reasonably standardized. So you probably won't see me using a commercial NAS (needing a web browser to navigate and up-/download my files, say what?) nor would I use something like Mega, despite being encrypted. I don't like lock-in into certain clients to speak some proprietary "secure protocol". Same reason why I don't use ProtonMail or that other one.. Tutanota. As a service, use the standards that already exist, implement those well and then come offer it to me.

But yeah. Self-hosted DNS, email (modified iRedMail), Samba file server, a blog where I have unlimited editing capabilities (God I miss that feature here on devRant), ... Don't trust the machines nor the services you don't truly own, or at least make an informed decision about them. That is not to say that any compute task should be kept local such as search engines or AI or whatever that's best suited for centralized use.. but ideally, I do most of my computing locally, in a standardized way, and in a way that I completely control. Most commercial cloud services unfortunately do not offer that.

Edit: Except mail servers. Fuck mail servers. Nastiest things I've ever built, to the point where I'd argue that it was wrong to ever make email in the first place. Such a broken clusterfuck of protocols, add-ons (SPF, DKIM, DMARC etc), reputation to maintain... Fuck mail servers. Bloody soulsuckers those are. If you don't do system administration for a living, by all means do use the likes of ProtonMail and Tutanota, their security features are nonstandard but at least they (claim to) actually respect your privacy.

!rant

Someone posted a link to a 30-day-security-challenge here on devRant some time ago and I just thought well, why not try to migrate away from the big companies - I've been using OneDrive as my only cloudstorage since the time when it was called SkyDrive and I've been hosting my Emails at outlook (via Live Custom Domains, a service that does not even exist anymore) for about 8 years now. Since I've always been lazy and since exchange activesync is a great feature if you have multiple calendars and want to sync them and your contacts to several devices I never tried to switch but now I am half done with migrating my data to my own nextcloud installation and my emails to my own mail server - since I don't want to loose the exchange functionality I am also setting up Z-Push and oh boy, this thing is bitching around but my webmail is already nicely integrated into nextcloud, IMAP / SMTP is up, configured and secured (still have to mess around with spamassassin as this email adress is floating around the web for about 10 years now). The only things to do is to get Z-Push work with STARTTLS and the card/caldav backend running and then the basic setup should be done.

I am just wondering if someone could hand me over a guide on how to sign / encrypt emails (GPG?)