Excellent advice.My Sting does that and I compromised by letting him give a warning bark. Then I would go to the door - Sting would have to sit beside me and be quiet. I didn't open the door until he was quiet. Giving him his bear to mouth also helped. I also rewarded him with treats when he was quiet. It takes a lot of practice. It also helps if you have some volunteers who will knock on the door and wait.