Yes, definitely show the dog each and every time a guest comes over how to behave. Take him on leash to the door, have him sit/stay while you open it and then take him back with you, again on leash, and have him sit or down/stay at your feet until he calms down and gives that "big sigh" that says he's given up. Then you can quietly unhook the leash and let the dog greet guests in a more calm manner.
If we don't give the dogs guidance and show them consistently what is expected of them, they don't learn and will be instinctive. And in Boxers, instinctive means jumping up and licking guests' faces.

By simply saying no and not showing the dog what he is expected to do, he will never know and not ever behave as you wish him to.
Do a search here using search terms such as "jumping" and you'll find tons of useful information.
Good luck.