IRB Law 9.A (Definitions) restrict scoring to trys, conversions, penalty goals and drop goals. A punt through the posts is just another kick into the try zone. And not a good one either, as the ball will almost certain keep right on going over the dead ball line. That means a scrum (with the put-in to the other team) at the point of the kick.
No unless it is either drop goaled or off a tee for a penalty :D
No. Occasionally a player will go for a drop goal and mistime his kick and punt it. Even if it goes through the posts the referee will signal no points as it was not a legitimate drop kick.
Facepalm. No! it has to be a drop goal or off the tee.
No, it must be a drop kick.