This is a fresh built ESX 3.0.2, build 77863, fully patched. When I VMotion a VM into it, the VM lost network connectivity. The VM is the only powered on VM in this ESX host. After I unchecked and checked the Connected option in Edit Settings, the VM picked up it network connectivity. I created a second network port group with the same VLAN ID but different network lable. The VM lost its network connection after I change to the new port group. I had to either move it back to the original port group, or disconnect and reconnect it before it can pick up its network connectivity.
When I moved another VM into this ESX with into the same port group. The VM lost network connectivity, but it is able to communicate with the first VM since they are using the same vSwitch in the same port group.
I used a scripted to set up the network in this ESX alone with a couple other ESX servers. I talked to the network guy, and he said its network setting is identical with other ESX servers in the same cluster.
Kind of lost here. Anyone has any idea? Any help would be appreciated.
Maybe my ideas will help you:
1) Your ESX hosts are connected to different physical LAN switches. If you move a VM from one ESX to another your switch is not able to refresh MAC address table.
2) Your VM's MAC address is assigned twice.
The thing is that the VM works flawlessly on other ESX hosts. It only happens to this particular host so far. Normally during VMotion, ping would drop one packet at most. In this case, it is the VM completely disconnected.