17mnth old German Shepherd

Question
I have an 85lb male GSD who I'm having difficulties walking and when guest
come into the house. He walks well on the leash, doesn't pull and walks
behind or next to me the whole time. However when another dog comes near
or even people, he lunges and starts pulling on the leash. He has been
trained extensively in obedience and agility. I have tried everything and I can't
figure out why he acts like he does. He's been socialized at the dog park since
he was 3mnths and doesn't act this way there. Any suggestions would be
greatly appreciated, we have a baby coming and I need to be able to walk him
with the baby!

My second issue is when people come to the house, he barks like crazy and
lunges at the door. Once people come in he is so excited that he runs into
them, nudges them with his nose and nips. Eventually he calms down but it
takes a while before he gets over the new guests. The pushing isn't really that
bad but the biting/nipping is really not okay. It's almost a play bite but he's
not a puppy anymore and he's too big to be "playing" that way. We have tried
spray bottles, holding his jaw, correcting him immediately; everything and
nothing has worked! It seems like it may be a reaction out of fear. How do we
stop it!?

He is a wonderfully sweet and good natured dog when he's relaxed and we
want our visitors to see what we see everyday! At the park he is amazing, very
calm and gentle with everyone but at home and in our neighborhood, it's
another story!

Thanks for the help.

Answer
I see many such questions.  It is quite possible for a dog to obey commands perfectly, and still not understand the owner is the leader and the dog needs to be submissive to him.  Any class that fails to to teach the owner how to play the role of the leader is a very poor class.  Start at www.dogbreedinfo.com./topdogrules.htm  There is some additional material there on dogs and children you need to read.