If your dog rushes the door to bark at or bite your visitors, obedience training is needed as a foundation to control the problem. Your dog should be put into a "Place" command or a "Down-Stay" until the visitor enters and is greeted as a friendly person by you, the leader. The dog can then be released when the excitement is over, to smell the visitor and to say hello. Training for these situations will teach the dog how to behave when visitors arrive. Teaching your dog to defend you against a criminal attack (personal protection) is one thing. But only with proper obedience training will you make the decision as to who is a bad man and who is not. And what happens when you are not around? Now your dog is in charge.