Your dog should definitely not be biting people. If he were to bite a stranger, they could call animal control and your dog could be taken away, and maybe even euthanized. You don't want that. There are many reasons why your dog could be biting people. It doesn't sound like he wants to hurt anyone, but is biting to appear intimidating to them. It would be best for both you and your dog, to find a professional dog behaviorist that can go out to your home and evaluate your dog. Once you know what is causing the problem, you can work with your dog to fix it, with the help of the dog behaviorist. It can be a little bit pricey, but it would be well worth it to fix this behavior. Good luck with your dog.