I've been asked by many student if you could VMotion over a gateway. While VMotion over a gateway is certainly not recommended, I just confirmed you can.

Here is my network setup:

esx2 Network Configuration

esx2 Routing Configuration

esx4 Network Configuration

esx4 Routing Configuration

My gateway is in the 192.168.2.x network on 192.168.2.100 and in the 192.168.1.x network on 192.168.1.100. VMotion VMs to and from esx2 and esx4 was no issue at all! Also, the vmkping command confirms a ping reply. My Nostalgia virtual appliance VMotionned just fine .