Cannot access modem diag screen

Just got a new MB8611 (my own) and prior to configuration change (speed increase thru comcast) I was able to see modem diagnostics (which I monitor for SNR and strength) via 192.168.100.1

I now see these ports are filtered by the modem, and I am no longer able to monitor.

Why does comcast lock me out of my own modem now?

Can this be re-enabled?