You also mentioned these points in your other comments here, but, to me, they look over the top to the point of being paranoic. That's probably because I lack a

You also mentioned these points in your other comments here, but, to me, they look over the top to the point of being paranoic. That's probably because I lack any serious experience in admin side of things, nor of working in environments where such measures would be required. So I wanted to ask: where such a level of security would be required? And also, what attacks does it defend from?