at 9 months old i was walking my male gsd when a person came around a car (about 20 ft) start barking and lunging at the end of leash imy reaction was also startled i laced him with the end of the leash sat him down and let the person come up to him and pet him every thing was fine. I had to put up with a dog that was alittle leash shy for about a month but have not had a reaction like that since. did i over react because of dog was leash shy for awhile

If you were startled too, then "atsagooboy." HE DID HIS JOB! Since you evaluated the situation and determined that there was no threat, your response may have been more that your dog could handle, since he was "leash shy" for a while. In the future, maybe "Gooboy", "down" and "leave it" would suffice. What are your goals for him?

imy reaction was also startled i laced him with the end of the leash Just what exactly do you mean by that?

It does sound like you overreacted. Your goals for this pup would make a difference in how you would react to this kind of situation, I would think.

For example, I don't want my SAR dog to be startled and react aggressively at the sudden appearance of a person, so I have done some specific "surprise" exercises with her. I have a person pop out from behind a building or tree or shrub and toss yummy treats to her. After several of these with different people, she now looks around corners expectantly whenever we go walking. A week or so ago when we were out for a walk, a man came unexpectedly around a corner, and my dog just looked at him like "where's my cookies????". I was very pleased, because this is the response that I want.

I also noticed that during the training sessions, she started sniffing the air before we would reach the corner, to where she knew before she even saw the person that they were there. This has carried over to our regular walks, making true surprises a little less likely.

If you don't want your dog to see every person as friendly because that would interfere with whatever goals you have for your dog, such as protection work, then you would probably handle it differently than I did. However, I would think it might be of some benefit to work on "surprises" by setting up controlled "surprise" situations, maybe just with a different focus, such as obedience/control. I doubt that even if you're doing protection, you really want your dog to light up every time some poor schmoe happens to come around a corner, right?