Hi,
Hi really don't understand, I experiment the same problem and this solution won't work for me 
!!!
How to install vmxnet3 driver for a virtulized ESXi host ? Modify the vmx file is not enough :
here my .vmx file:
ethernet0.present = "TRUE"
ethernet0.connectionType = "custom"
ethernet0.virtualDev = "vmxnet3"
ethernet0.wakeOnPcktRcv = "FALSE"
ethernet0.addressType = "static"
here my host after a reboot:
~ # esxcfg-nics -l
Name PCI Driver Link Speed Duplex MAC Address MTU Description
vmnic0 0000:02:00.00 e1000 Up 1000Mbps Full 00:50:56:3b:8c:37 1500 Intel Corporation 82545EM Gigabit Ethernet Controller (Copper)
Here I find another solution :
http://communities.vmware.com/thread/433886
But it is not sustainable...
My environment is really simple (for the moment):
2 ESXi hosts
1 Win (AD) host
Communication is ok in all way except between the two ESXi hosts.
Who make his kind of lab and dont have this problem ? I try to change network configuration in VMware workstation, my IP configuration is OK (I'm really sure about)
Thanks for help !