[ofw] HPC server 2008 IPoIB disrupts compute node Windows Update service?

[Smith, Stan]

Hi Fab,
  Do you have any theories on why/how IPoIB could disrupt Windows update service?

We have an HPC Server 2008 cluster configured such that compute nodes, which are not directly connected to the enterprise network/Internet, use the Private Ethernet (NAT enabled) to communicate with the Head node which holds the enterprise/internet Ethernet interface.
Once the compute nodes IE8 proxy is setup correctly, the compute node's windows update service works fine (downloads & install OK).
Head-node Windows update service functions normally with IPoIB enable or disabled.

After a WinOF installation, IPoIB enabled and static IPv4 address set on the compute node's IPoIB interface, the windows update service just hangs when windows update is run.
It isn't until the IPoIB interface is disabled does the Windows update service resume normal operation?

What is it about IPoIB and HPC compute nodes?
We do not see the Windows update service problems when WinOF/IPoIB is installed on vanilla server 2008 or 2008/R2?

Thanks,

Stan.