Has there been Internet / Comcast DNS issues recently?
Starting about 4 weeks ago, I have had regular DNS problems. Everything will be running just hunky dorry, then suddenly, everything stops. I'm running WIN 10 and I get a NO INTERNET Access on the task bar icon. Sometimes this resolves on it's own, sometimes I have to power cycle the router that sits between my workstation and the cable modem. It's not just the one machine. Others in the house will have the same problem at the same time.
!-800-COMCAST troubleshooting is no help all they want to do is run a health check, which is going to fail if there is no DNS and then restart the modem. When that doesn't fix it, I'm offered troubleshooting at 49.95 (not going to happen).