Expert: Brian Benosky - 3/27/2008

Question
QUESTION: I've heard that a PC connected to the Internet via a cable modem is always vulnerable to hacking whenever the PC is on. I notice that when I log off/turn off my PC, the cable modem PC ACTIVITY light stays lit/flickers.  The other day, I cold-rebooted the PC by using the ON/OFF button on the computer.  While the computer was OFF, the PC ACTIVITY light went off, too.  Question:  Is it safe to turn the PC off by using the ON/OFF button?  Or, is it safer to use the LOG OFF feature -- even if the PC ACTIVITY light stays on?

ANSWER: Hello Alida

When you log off, you are still leaving the computer open for attack.  The PC is basically still on, but waiting for instructions.  These instructions could come from you, or from an attack online.  The correct way to power off is to Click Start-ShutDown-Turn Off.  This will shut Windows down safer than hitting the power button.  Your PC will then be disconnected from the internet and will not be vulnerable to attack.  I hope this helps, and if you have any further questions, please let me know.

Brian

---------- FOLLOW-UP ----------

QUESTION: Thanks, Brian.  I guess I should have been clearer.  When I said I "log off" I meant that I (always) turn off the PC by clicking Start/ShutDown/Turn Off.  After I do this, the cable modem's PC ACTIVITY button stays lit and flickers.  The only time I use the Power Button on the PC is when I want to "cold-reboot" the PC if some program isn't working.  It's only when I cold-reboot (and the computer turns OFF) that the modem's PC ACTIVITY light goes out.  So, my question was -- since the modem's PC ACTIVITY light goes totally out when I "cold-reboot" -- is this safer than when I click "Start/ShutDown/Turn Off" -- since the modem's PC ACTIVITY light stays on, then?

Answer
Hi Alida

The short answer is no, it's no safer.  The longer version is more technical, but it has to do with how your modem "sees" your computer and how your power supply works.  The modem is always on and is always looking for your computer to connect to, as long as your power supply is sending power to your PC's modem.  The two modems keep talking to each other in anticipation of you turning your computer back on.  When you "cold-boot", you are stopping the electric supply to the PC's modem, so the cable modem has no one to talk to and the activity lights stop.  But in either case, no actual viruses can pass from one modem to the other.  I hope that made some sort of sense :-)

Brian