Hello and welcome to COL
From your description it sounds that your boy becomes so excited, maybe anxious too, when somebody comes to the door that he goes way over his threshold of being able to stay calm and loses self control.
One of my two (Louis) does something similar, although admittedly without the snapping at feet. He associates the doorbell and the front door being opened with the possibility of strangers coming to the house, which makes him worried. Once he starts barking my other one joins in as well, although he likes visitors! So I've come up with some strategies to help me and the dogs cope with the situation.
The first one is to have a physical barrier (a baby gate across the hallway) so that the dogs can never get to the front door. That in itself takes some of the pressure off Louis because he simply can't get there to bark.
The second one is that I've trained the dogs to go into a room off the hall and be shut in there while I answer the door. When the doorbell rings they still get up from wherever they are and bark, but then they go into the room and after a few seconds they're quiet (mostly) and just lay down in there until I let them out.
If the person at the door is a visitor and comes into the house I leave the dogs shut in the room until the visitor has settled (if they're dog friendly) and then open the door to let the dogs in, having asked the visitor to completely ignore the dogs. The friendly, confident dog comes in to say hello. Louis may come in and stay near me or may choose to stay in the room. His choice, and that's fine by me. If he came in and started barking I'd put him back in the other room, not in a harsh way or as a punishment, but to give him the chance to calm down.
It's finding out what works best for you. If you can find a method that stops the situation from escalating in the first instance both you and your dog will feel more relaxed.