I open the door just a crack, surrounded by 5 dogs of all sizes and breeds who are always madly barking their heads off. The five include two Pit Bulls and a German Shepherd----none of whom would hurt anybody if he spoke to them nicely and offered to pet them, but it's the look that counts! The herd of mutts scares off anybody without a legit reason to knock on the door. They often go away before I get downstairs to open it.