re: Home defense system: Your dogs?

My dog will bark occasionally and even let out a bit of a growl but she is not being protective. She is a lab and the moment someone walks in our door, complete strange or not, she jumps all over them and just wants to greet them. It is not in her nature to be a guard dog. However, most people don't know that if they are outside the door and hear a big dog barking/growling so I think she still works to deter anyone from breaking in.