The activity light on my Motorola SB4200 cable modem doesn't flash anymore. It stays on constantly. The light on the back of the modem is still flashing and so is the activity light on my router. I can find no incoming or outgoing bytes on taskmgr and tcpview shows no established connections. Sygate firewall shows no incoming or outgoing connections. Is there anything that my isp (Cablevision) could be doing that would cause this, or is my modem getting ready to die? Signal strength and throughput is unchanged.
Yes, the cable company can have an affect on how that light works. What's been "normal" flickering of the light is often arp traffic, so that flickering doesn't necessarily coincide with any established connections on your computer. Two possibilities are that arp traffic has increased to the point that the light no longer flickers, or the firmware has been updated, and the cablemodem has been configured for the light to act in that fashion.
(Remember, firmware updates are pushed-out by the cable company, and the config file that configures the firmware is also something pushed-out by the cable company.)
So that's two ways what you see may have changed.
As for the other possibility that your cablemodem is "getting ready to die", I would say that's an unlikely only way for it to show. If it is a modem problem, and the only thing that has happened is a short in a single circuit that has caused this lamp to stay on steady, that's no indication that any other failures will occur. Think of it this way: If the light bulb in your oven were to continue to stay lit even when you close the oven door, does that mean the oven is getting ready to fail? It's a long-shot, but it could mean that, but it's far more likely that the problem is with control of the light.
Thanks Warren, that's what I thought it might be and to test it I installed a newer modem that I already had (SB4220) and the activity lights behavior went back to normal. The upstream signal strength went from 49/50 to 45 so all is well. Thanks for the info.