How To Stop Your Dog Jumping Up On People
There are several approaches to stopping your dog from jumping up on people.
The quick-fix solution to stopping this behavior is to have your dog on a leash and to step on the middle of it. When your dog tries to jump, he finds himself brought up short. This is sort of the self-correcting management approach. You should immediately praise and treat your dog for not jumping.
The more long-term solution for not jumping on people is to teach your dog to sit when there is a knock on the door or the doorbell rings and people enter. You can practice this behavior with a friend. Have your friend knock and you tell your dog to "Sit." Treat. Tell your dog to "Stay." Open the door. Your dog has to stay sitting! You can see why this is a more long-term solution since it involves several commands. But, it's important that your dog learns that he must not run out the door when it opens, whether you are letting people inside or you are walking out. When your friend walks in the door, have her give your dog (still sitting) a treat.
You can practice having your dog sit at the door when you have real guests come over. Hand your guests treats and ask them to give them to your dog (who is sitting nicely for them).
It may take a lot of practice to reach the point where you want to trust your dog at the front door with real guests, but it will be worth it.