Seems plausible in Salt Lake City (Score 1)

I've noticed for some time that it seems whenever comcast dns is not working (and this is *very* frequent, for periods of 15 seconds to a minute, as often as not), that neither do any other dns servers. I ran a test just now, periodically doing lookups through comcast and through 4.2.2.1, and there appeared to be a very high correlation between failures of the two. At the same time, I was also running a ping out to google, and it never missed a beat. This would suggest that either comcast is proxying dns traffic, or does some weird traffic shaping on port 53.