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Here's our home setup: we have a wireless router, connected are 2 desktop PCs (let's call them A and B), plus we also have a laptop that connects to the router via wi-fi. Desktops A and B are connected via LAN wires.

Given that, the problem is that every time desktop A starts up or shuts down (it seems to be simply on power up or power down, the OS it's booting into doesn't matter), the wireless connection is reset, i.e. the laptop literally loses the connection and has to reconnect. No such problem happens when restarting desktop B. It's a bit of a pain when I'm playing online games or something over the laptop and desktop A reboots.

I'm not sure what to check for here...would it be a problem with the router, with the way the network is set up, or something else?

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Are A & B connected to the router via wi-fi or wires? – ChrisF Sep 5 '09 at 14:37
What model is the router? Can you use your connection at all with A down, even if you have to reconnect, or does it have to be up and running for wireless connections to work? Does your router have the latest firmware? – MDMarra Sep 6 '09 at 2:51

If you are using a battery backup on Computer A and also have the router connected to the battery backup, there might be a chance that Computer A is in the 'Main Power' plug. On some battery backups, there is a button indicating that if the 'Main Power' is off it turns off the rest of the power for the battery backup. If that happens, then it will turn off the power to the wifi as well.

Just a thought... I had this happen to me once and it drove me nuts until I actually looked at the battery backup.


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obviously comupter A is sending a signal on power on/off that doesn't go down too well with the router. if i were you, i'd replace the NIC in computer A immediately.

the only option i can see remotely being related to the problem would be WOL (Wake on LAN), check the BIOS if it is enabled and turn it off ... just a wild hunch.

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WoL wouldn't have anything to do with this. Assuming it was trying to wake something from LAN, all it does is broadcast FF FF FF FF and then the target's MAC 16 times. This will wake the computer who's MAC Address matches the broadcast. This message is ignored by anything not matching that MAC Address. – MDMarra Sep 6 '09 at 2:49

(Assuming, of course, that at least the desktop machine in question has a wireless card...if it doesn't, well, disregard this answer)

My guess is that you are experiencing some version of:

  • Desktop A is on 802.11b
  • Desktop B is on 802.11g
  • Laptop is on 802.11g

When the Desktop A shuts down, the entire network flips over to g (causing a temporary loss of connectivity), and then when it comes back up, the router resets to b again (causing another temporary loss of connectivity). This could also happen with g/n, b/n, etc.

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up vote 0 down vote accepted

This question seems moot now. After we changed the video card on the desktop causing the problem, it no longer occurs! Sorry!

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