SMTP: nope, the server accepts your connection before you do anything VoIP: generally negotiated somehow before the UDP "pushing" happens scp: just because in

SMTP: nope, the server accepts your connection before you do anything VoIP: generally negotiated somehow before the UDP "pushing" happens scp: just because in your mind it's a "push" doesn't make it so. In reality the other machine is sending you acks, without which your machine wouldn't continue "push"ing and thus, again consent is required. finally you're logged in to that other machine which nearly universally equates to consent