I have a CM1100 that started having issues today. It will not connect to my router. It will, however, connect directly to a laptop.

My setup is:

ISP -> CM1100 -> Router/Firewall -> APs & Switches

But the link between the CM1100 and Router/Firewall doesn't work.

If I change things up:

ISP -> CM1100 -> Laptop

Everything works just fine.

It does not matter which port I connect to on the CM1100.

Here are my troubleshooting steps:

Power cycle the modem and Router/Firewall
Check the coax connection on the CM1100
Try both ports on the CM1100
Try different WAN ports on the Router/Firewall
Try different cables with steps 2 and 3
Connect my cellular modem to the Router/Firewall and verify that internet works on both WAN ports
Try different cables between the cellular modem and Router/Firewall
Try a new Router/Firewall on the CM1100, repeating steps 2, 3 and 4
Pick-up a modem from my ISP and verify it works with both Router/Firewalls

So, I'm at a loss as what to do next. No matter what I do, I can't connect to the CM1100 through a Router/Firewall, only directly.

Has anyone experienced this?

Forum Discussion

CM1100 won't connect to routers