Duke goes absolutely nuts! He also goes running to the door if he hears a doorbell on tv. He barks nonstop and all the hair on his back stands up. He's a very good guard dog and I never scold him for barking when someone comes up to the door. Especially people like the pool man and the exterminator. I don't want him getting used to them, even though they may be harmless. These are just the type of people that can sometimes commit burglaries later.