Discussions

My husband and I own an almost-3-year-old mixed breed pup (terrier sized) who we adopted at the age of 6 months. He is truly our baby and we love him with all our hearts....however, he is displaying some really scary behavior problems that have us desperate for help.  
 
The issue is that he is very protective and aggressive with anyone that comes into our home, to the point of "nipping" visitors. Unless he knows them very well (ie: close family members) he barks and growls incessantly, and if they turn their back to him he will run up behind them, rear up at them on his hind legs and nip at their hand and shirt.  
 
We have started keeping him on a leash when visitors come over, and that helps a bit, but it is coming to the point where we are scared to have company over, especially children....we are so terrified that he will attack!  
 
We took him to puppy obedience classes when he was approximately a year old, and he gets lots of exercise every day. We have done research on techniques to stop his behavior (Dog Whisperer type stuff) but nothing seems to help.  
 
He has never displayed any sort of aggression with myself or my husband, and he is in fact the most gentle loving dog when alone with us....but his behavior with strangers and visitors is heartbreaking, and we are desperate for help.  
 
Does anyone know of anyone we could contact for help, especially for one-on-one treatment or in-home training? Any ideas or suggestions from other animal lovers in the community would be more than welcome.  
 
Thank you so much for your time.