Hi All,
Our system has been working fine for 8 months without any issue until installing ESX 4.1 U1 and the latest network driver. We have 2 x HP DL580 G7 each with an inbuilt NC375i Quad port NIC and 2 x NC375T Quad port NICs (using driver 400.4.0.585) - so thats 12 NICS per host. 4 NICs per host are teamed together for our production LAN. We have 2 Cisco/Linksys Layer 2+ switches which each take 2 connections from each host, and are linked together using with a 4 port trunk using LAC.
Issue: We have approximately 24 Guests - Windows Server 2003 or 2008 mostly. If we migrate or restart a guest machine, the networking on the guest stops working - we cannot ping to or from the guest. If we then shutdown the guest, remove the network interface and re-add it, start up the guest, the network then works fine again. The only thing that happens from removing the NIC and re-adding it is the MAC address changes.
I dont even know where to start at looking at this. Anyone have any ideas? 