I have read a few days ago that there was a huge Comcast outage related to some DNS configuration error. They claimed it was fixed in an hour but in fact, I had problem for hours. Since then, my internet connection is on and off. I constantly see DNS problems.
Unfortunatly, I can not even reach Comcast Support to tell them (I am sure they do know anyway). 1-800-Comcast keeps me on the line for sometime and then disconnects, so called direct number, 1-877-6373128, is always busy. I am not sure if this is specific to NJ :(
Well, this turned out to be yet another DNS related issue. After a week of on and off connection, finally they got it right.