I need to prevent mobs from getting into my shelter, and I have an exposed lower area with a ladder leading up to the shelter proper. If a zombie or something spawns down there at night, can it reach me in my shelter?
While mobs are technically capable of climbing ladders, the pathing AI generally prevents them from doing so – instead, they will typically just spin around in circles.
In general, the best way to restrict access to a shelter is to build a Door.
Source : Link , Question Author : Invader Skoodge , Answer Author : LessPop_MoreFizz