Remove the “Last login” message from the Terminal
touch .hushlogin
Enable/Disable Firewall
defaults write /Library/Preferences/com.apple.alf globalstate -int 1
0 = off
1 = on for specific services
2 = on for essential services
launchctl load -w /System/Library/LaunchDaemons/ssh.plist
launchctl unload -w /System/Library/LaunchDaemons/ssh.plist
launchctl list | grep ssh