I disconnected the doorbell because when that thing rang, she did like a screaming bark and very loud, almost gave me a heart attack and made her crazy. Anyway, If there's a knock on the door she is all over it, hair standing up, barking....but I say it's okay, look who it is, say Hello....and then she's fine. She's adapted to people. I'm not sure what she would do if an intruder came in, pretty much she would not let them. I'd be scared, she's very protective. Sometimes they just don't like someone and that's that.