[yorkie mad]

To the op- is your dog quite young? Tia used to be like that in the early days , as soon as the front door opened it was like freedom! They are just curious little devils , theres a big wide world out there they want to investigate and they don't realise its not safe. Now however I can be in the front garden and Tia will stand at the door and watch and won't come out unless called. Hopefully your baby will grow out of it but in the meantime put him in an xpen when someone knocks the door a bit of training will go a long way. My two hear the word "bed" when someone knocks the door and they both go to it and it didn't take long for them to learn.