I have a rescued dachshund that I was told did not like children. It turns out that he does not like anyone that isn't family. He is 7 years old, and has been neutered for the last 2 years. Whenever anyone comes over, even if he has met them before, he will bark, growl and snarl. I have to tell people to stand very still and not try to touch him until he is through. If they try to pet him, he will bite hard enough to draw blood. Once he is through barking and snarling, he will jump in their lap and be their best friend. How can I stop him from doing this? I'm glad that he won't let outsiders hurt us, but the fact that he won't let friends visit is a problem.