[Maximo]

My boys love doing battle with the big brown beast that is the UPS truck. I've tried introducing them to the truck when it was parked, but they are still convinced that it and its driver are enemies.

I agree with Brit, I don't mind when they bark at the doorbell, but they need to quiet down when I open the door.

If your pup is biting in these situations, that means he is in "the zone" and thinks there is real danger. Have friends or family help you do training exercises. Check out Victoria Stilwell's books and videos (online). One of her methods is to put a rug next to the door and then teach the dog to go to the rug and sit before the door is opened. I keep my boys gated off from the entry way, so their place is at the gate.

First teach your boy to sit nicely on the rug using lots of praise and yummy treats. Then have your helper ring the door bell or knock and teach your dog to sit quietly on the rug. This will take a lot of repetition and patience. If he goes bananas, stand perfectly still and watch until he calms down. You may want to keep him on a leash at first during the exercises to keep him from biting you. Once he is calm, praise and give a treat. Don't attempt opening the door until he is calm. If he acts out when you open the door, close the door immediately. Once he is calm, try opening the door again.

Good luck.