[TelstraClear] Constantly flashing PC/activity light

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timmmay

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#13347 5-May-2007 13:51

The PC/Activity light on my cable modems (PC and TV) both flash constantly, which makes the lights on the router flash. I know it's pretty silly but I wondered if anyone knew why they do it, even when the PC is turned off.

freitasm

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#69600 5-May-2007 14:03

Any background activity or broadcast that is directed at your IP address will go through to the router...

ZollyMonsta

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#69605 5-May-2007 14:36

timmmay: The PC/Activity light on my cable modems (PC and TV) both flash constantly, which makes the lights on the router flash. I know it's pretty silly but I wondered if anyone knew why they do it, even when the PC is turned off.

Hi Timmmay,

That simply means there is a connection between the cable modem and your computer/set top box.
If there is no connection, that light will go off.

It's Just a visual display of connectivity.

Cheers,
ZollyMonsta

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timmmay

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#69614 5-May-2007 16:23

Thanks guys, seems strange that it constantly blinks and is constantly sending data to my router is all.

michaeln

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#69737 6-May-2007 23:09

It's ARP traffic mostly. (Well, that and the normal background malware attemtping to pwn ur pc :) The cable modem network is like an Ethernet switch. All the PCs on the local 'switch' send broadcast ARPs to find out the MAC address of various devices---such as the gateway router. Being broadcast, it goes everywhere on the local segment. That adds up to a constant background chatter. For which you are not charged by the way.

timmmay

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#69739 6-May-2007 23:14

Thanks Michael, that makes sense. The router light flashes constantly too, I guess the modem passes most everything on the router, which drops most of it before it hits my PC.

CiscoDan

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#71695 22-May-2007 14:31

Hi, I have seen the same thing. I have had a look at the traffic, and can see that there is a lot of ARP traffic from the gateway, and also DHCP requests from the modems that come with digital TV. :-)