Comcast has been on-and-off about doing it. They've switched between proper NXDOMAIN and hijacking it a few times. I don't have Comcast anymore (not even avail

Comcast has been on-and-off about doing it. They've switched between proper NXDOMAIN and hijacking it a few times. I don't have Comcast anymore (not even available in my area), I can't tell you if it's current practice.