Plugging it,,well who knows how far down it rusted into,,but plugging the end oughta be simple enough,,maybe stick a rag in it and fill with that expandable foam stuff,,or stick a rag way down in it and fill with a concrete of some kind,,maybe a rubber end cap,,,just gotta stop odor and water,,maybe its not in that bada shape futher down,thats the bad thing about concrete around lines,,maybe get you a jack hammer of some kind and have at it,,,but if you don't need that drain anymore,,,plugging it should be simple enough,,,thingy