Place ham into a large pot, cover with water, and bring to a boil. Reduce heat to medium-low and simmer ham for 1 to 2 hours. Cut away and discard any rind and visible fat.
Preheat oven to 325 degrees F (165 degrees C).
Score the ham in a diamond pattern and place into a roasting pan. Stir Dijon mustard and brown sugar in a bowl until thoroughly combined; brush mustard mixture onto the ham. Press a whole clove into the center of each scored diamond shape. Pour peach nectar into the roasting pan. Combine pineapple and maraschino liquid in a small bowl.
Bake ham in the preheated oven for 3 hours, basting frequently with the pineapple juice mixture and peach nectar.
Arrange pineapple rings over the ham and secure with toothpicks. Secure a maraschino cherry in the center of each pineapple ring with a toothpick.
Bake ham until browned, tender, and fragrant, 1 to 2 more hours, basting ham and fruit frequently with pineapple juice mixture and pan juices.