Definitely not a Jack Russel. Except for coat color and the tail, it doesn't look like one. It appears to be a med/large breed puppy with a double coat. Except for the docked tail, it resembles an Akita puppy.
The thing is that this puppy has a very short tale and akita puppies doesn't. The other particular is its snout. As i said before maybe its a mix, it has a lot of common with akita puppy but theres a part left.
I really want to know what breed this dog is!