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I have a Windows Vista laptop here with an Atheros AR5007EG wireless card. When attempting to connect it with an AVM Fritzbox 7330 the following happens:

  • Laptop successfully negotiates DHCP and receives correct IP-Address, Router-Address and Subnet
  • Laptop broadcasts ARP-request for Routers IP
  • Router receives request
  • Router sends answer to MAC-Address of Laptop
  • Laptop never receives the answer

The laptop continues to send requests, the router receives them and answers but they never arrive. This goes on until I disconnect the laptop.

This problem doesn't occur on any other of my machines, connecting the laptop via ethernet cable does work.

So IMHO it can't be:

  • the operating system
  • the router

Any ideas where to look next would be appreciated.

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up vote 0 down vote accepted

When this happens, there are a few things you can do:

  • Place another wireless device in the network to see if it receives an ARP reply correctly.
  • Try a wired device in the network to ensure it's not a wireless issue.
  • Replace the wireless card with another known working wireless card.

If another wireless device works, you know the router is sending ARP replies correctly. If a wired device (preferably the same one) works, you know the issue is with the wireless card or wireless API/stack (and not with your Vista OS laptop). If you replace the wireless card with a known working good one and still have problems, it points to an Vista issue (have you installed all patches/service packs?). There are several known Vista wireless issues, like this one.

Since you have visibility at the packet/frame level, I assume you're sniffing the wire. Another thing to check is to ensure the address fields and content of the ARP reply are correct and within standards with no additional unneeded data.

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It was the updates. While automatic updates were enabled, Microsoft had deemed an update to the wireless driver as being optional – go figure. – John Sep 24 '12 at 22:19

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