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Ethereal-users: Re: [Ethereal-users] WinXPHome is active despite hybernate?

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From: Jerry Talkington <jtalkington@xxxxxxxxxxxxxxxxxxxxx>
Date: Thu, 27 May 2004 17:45:58 -0700
On Thu, May 27, 2004 at 03:04:24PM -0700, Jack Jackson wrote:
> At 02:13 PM 5/27/2004, Peter Marquardt wrote:
> >Several times I've seen one of the Windows XP Home boxes in my home 
> >network "connected" and "active" in the LAN. The light on the NIC and the 
> >switch are _on_ like if the machine was not turned off at all. Today I 
> >concentrated on that machine with Ethereal and found it to send ARP 
> >requests and announce its NetBios name/workgroup. It is the only desktop 
> >PC with Windows XP Home, the Notebook when booted into XP Home and 
> >hibernating doesn't show that behavior and even my running and online 
> >Linux / BSD boxen are less "noisy" on the LAN when idle than the 
> >hibernating XP Home box. It's perfectly quiet though, when Windows is 
> >actually shut down.
> >
> >Is that normal? I always thought hibernation is a suspend to disk followed 
> >by a power-off. (The machine also boots and recovers from HD upon 
> >power-on) If the OS isn't managing the NIC, who/what then?
> 
> Generally when hibernated all power should be removed from the entire 
> machine including the NIC.  However, some NIC cards have a 'wake on LAN' 
> feature'.  I don't know too much about it, but I think the idea is that the 
> NIC does still have power when the CPU is shut down and has the ability to 
> wake-up the CPU.  I would think that would apply only to Suspend and not 
> Hibernate.  It might be possible to turn that off by looking at the 
> properties of the NIC.

With WOL, the NIC still receives enough power to wake up the machine,
even when it's powered off, so it should still be listening when in
hybernating.

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