It is common for dogs to sniff each other's behinds and faces when they meet other dogs. As much as dogs would like to play with humans, our faces are located all the way at the top of our bodies, making it inconvenient.
Jumping up on people, for dogs, is often an attempt to behave according to normal dog manners. Dogs jumping up on people can be an indication of dominance.
Either way, this problematic behavior is rarely welcomed by strangers and should generally be fixed before it becomes dangerous - with little kids for instance who can not carry the dog's weight.
To resolve this common dog behavior problem, ignore your pooch when you come home until he stops jumping. Good action of ignorance is turning your back on your dog.
Never yell at or push your dog away in an attempt to make her stop. Those behaviors are likely to excite a dog and encourage them to jump even more since it appears to be a game to them. Once her feet land back on the ground, reward her by petting her and praising her so that she learns the reason you ignored her is because she was jumping up.