An L-footer is a great way to stop your dog from jumping over the fence if used a little differently. You’ll want to turn it upside down and use it at the top of the fence. Create the L-shape and securely fasten the short side to the top of the fence and have the rest of the hardware angled towards the yard so that when your pooch looks up they will see fencing.
Dogs with poor social skills oftentimes just don’t know better. They will bounce off of everything, jump on everyone, run around like crazy, and investigate everything they can get their paws, snout, and eyes on! These dogs can come from any background, whether a rescue or puppy from a great breeder; if they haven’t had experience in new places and new situations, this can be how they respond.
Why do dogs jump up? A plausible explanation arises from their ways of communicating with each other. A puppy greeting an adult dog often licks the adult’s muzzle -- a polite, deferential behavior. Dogs, of course, descend from wolves, among whom muzzle-licking is how pups get the grownups to regurgitate food for them. Domestic dogs rarely nourish puppies this way, but muzzle-licking has survived, maybe because deferential behaviors are handy for a social animal. Think of humans saying “No, after you.” Muzzle-licking is also an appeasement behavior -- something you trot out to de-escalate a fight. A human might lift up his hands, palms toward the person he’s arguing with.