YOu must condition train him. SO whenever he hears the doorbell ring instead of him barking redirect him with a toy or treat. However this is a natural instinct for dogs to bark and they are actually letting you know that there is someone there, and this is in a way a very good thing. This is the dogs job, i could see you not liking it if the dog was growling at a person you knew or something like that but it is not. This is a good thing believe me, if an intruder was trying to break in in the middle of the night you would want him to bark and alert you right? CUt the dog some slack and dont hate appreciate!!
