1. Turn off IPV6
networksetup -setv6off Thunderbolt\ Bridge
networksetup -setv6off Wi-Fi
2. Turn off Bonjour
sudo defaults write /System/Library/LaunchDaemons/com.apple.mDNSResponder ProgramArguments -array-add "-NoMulticastAdvertisements"
3. Turn off saving to iCloud by default
sudo defaults write NSGlobalDomain NSDocumentSaveNewDocumentsToCloud -bool false
https://github.com/drduh/OS-X-Security-and-Privacy-Guide