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Host: Debian 7.2 x64.

Guest Win 7 Pro 32-bit. Virtio disk drivers work flawlessly, but there's a problem with virtio net (netkvm something) drivers. Virtio drivers come from virtio-win-0.1-74.iso.

This network card works perfectly in win7 guest:

<interface type='bridge'>
  <mac address='52:54:00:ea:39:d5'/>
  <source bridge='br0'/>
  <model type='e1000'/>
  <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>

This one doesn't:

<interface type='bridge'>
  <mac address='52:54:00:70:c9:64'/>
  <source bridge='br0'/>
  <model type='virtio'/>
  <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>

Obviously I have installed the drivers from ISO, they show up in Device Manager as working without a problem. The card "just" does not seem to communicate with host - e.g. it does not show up in arp -n output on host.

I'm using Linux guests on the same host with virtio too and they just work, so can it be related to host config?

How can I fix that?

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Review the network configuration within the guest. – Michael Hampton Jan 4 '14 at 20:21
up vote 1 down vote accepted

By pure trial & error I have found that virtio eth cards work if I disable TCP Checksum Offload and UDP Checksum Offload in eth card config (guest OS: Win 7 Pro SP1 32-bit).

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