It has recently come to my attention that at least one major server manufacturer has recently switched from packaging the Intel® Gigabit VT Quad Port Server Adapter, which uses the Intel® 82575 Gigabit Ethernet Controller to the Intel® Gigabit ET Quad-Port Server Adapter, which uses the Intel® 82576 Gigabit Ethernet Controller. 


The problem that some are encountering is that VMware* ESX 4.0 does not currently have inbox support for the ET Quad-Port (82576) adapters.  The older VT Quad-Port (82575) adapters have inbox support from VMware, as do the Intel® Gigabit EF Dual-Port (82576) Adapters.


You can download the VMware ESX/ESXi 4.0 Driver CD for the Intel®  82575 and 82576 Gigabit Ethernet Controllers from the VMware driver download page.  The specific driver can be found here.  Note that while the 2nd link is valid TODAY, when the next update to the driver is published, this link may change and not be valid anymore, in which case use the first link here and search for ‘82576’ in the list of products.


The installation instructions can be found on the right side of the Driver CD download page, under the ‘Related Resources’ section, in Release Notes.