Rottweiler behavior

Question
My Rottwailer (1 yr. old) is very friendly and well behaved with the exception that when I'm walking him and I stop to talk to someone, when the person turn his/her back and walk away, my dog tries to chase him/her very aggressively.  Any suggestions?

Thanks

Answer
It sounds like your rottweiler is looking at this person as if they are "submitting" to him when they turn their backs on him.  I would suggest a pinch collar if you don't already have one.  This is what my trainer uses to train large dogs.  What it would do is when he goes to lunge at people the collar would give him a pinch.  At which point you would pull back on the leash and give him a firm "OFF".  Try this for a while and see if works for you.  If it doesn't, I would suggest hireing a trainer.