So, I spent the better part of a day trying to figure out why all my VMs were working like a charm, but my management network was pretty much hosed.

By hosed, I mean it was pretty unusable. It would sputter, and occassionally give me info, but more times than not I would get connection errors.

So... Here is what I figured out...

I bought a new NIC for my host, and put the old one into a different machine on my network.

What appears to be happening is my ESXi server, which the new NIC is still broadcasting the MAC address of the other card, even though the proper MAC addresses appear on the console in the network configuration screen.

I know this because when I switch the management network to use DHCP for the IP configuration, I can clearly see the other MAC address in the log.

I have taken the old NIC off the network and everything is currently fine.

So, how do I figure out where this left-over MAC address is being caches, and how do I fix it??