In a house we are remodeling for rental, it has a laundry room which is preety far from the main drain lines. Rather than a vent going up through the roof, it has an inside vent which I've never seen before (note: the kitchen sink has one of these also), which can be seen in the attached pic (assuming I'm successful making the attachment). Is anyone familiar with these? Does this suffice for a vent or do I need to redo to the outside? Thanks for any responses.