Interdasting network issue

[Shambler]

Break down of all this.
Machine 1: Phenom (Asus mobo, Phenom II X6, 16 gigs o ram, onboard NIC)
Machine 2: ESXi (Gigabit mobo, LLano quad, 16 gigs o ram, onboard NIC)

Long story short, I swapped mobo's between the two boxes. (Proc and Mem stayed on mobo during transfer)

Reinstalled Win7 on Phenom. ESXi is on the same config.

A wild conflict appears! When Phenom is connected to the network ESXi drops connection. From my laptop if I ping ESXi, it will drop roughly 4 pings then respond with 2 then drop 4-6 then respond with 4-6. Odd behavior.

Now when pinging ESXi from Phenom I get Destination host unreachable and the IP listed is the IP for Phenom.

If Phenom is disconnected from the network ESXi pings great. From my laptop I can connect via vSphere and start launching VM's.

So I assume that if I were to reinstall ESXi this would clear up. Or if I were to get a new NIC for one of the boxes and disable one of the onboard's this would clear up. I'm sure as hell not rebuilding ESXi as I have a test coming up and I still want to lab a bit.

So, what I plan to do/test today: Grab a NIC from Fry's/Microcenter. Throw it in Phenom, disable onboard, and ping everything and everyone. If that does not work I'll simply disconnect Phenom and lab from my laptop until I take my test, then rebuild.

Figured this may be interesting for some of you.

 

[bmh.01]

Is the management vmkernel adapter is holding the mac address of the old motherboard? Hence causing a conflict.

 

[Shambler]

Thanks BMH.01!!!

FOUND IT! So, should I just change a character or two on the Phenom's address? If so, can it be any character in the string?

Note: When I first checked ESXi, I thought I was fine there:

____________________However____________________

Phenom:

ESXi:

 

[Shambler]

Changed one character of Phenom's MAC. Problem solved. HUZZAH!

 

[goodcooper]

yea, switches don't like that...