Hello Techie01,
i don't see a "/var/log/vmkernel.log".
So I try to be precise as possible.
Long Version:
The VM's with the Problem started in 2009 on ESX 4.0, Same Dell R610 as today. They where new created Server 2008 VM's, VMXNET 3 Adapter with MAC Adress in Range 00:50:56:BC:XX:XX.
VM Version 7 for all these VM's.
The Problem only exist on Server 2008 32 and 64bit VM's. No Problem with WinXp, Server 2003, Server 2008R2, Server 2012R2 VM's.
Also I have no Problem with Vmotion, this worked fine. I was also be able to work in these VM's with the Vmware C# Client. With the Client I could reboot the vm an so on.
So, "just" these VM's could not access the Network after Vmotion from ESXi 5.5 2718055 to ESXi 5.5 U3 (3029944).
My 2 ESXi 5.5 Host are nearly the Same. Dell R610, 10 NICs, ISCSI SAN.
And the Problem only appears in the Server 2008 (Windows Vista code?) vm's.
As these are my 2 only Servers I am not able to do more testing.
For testing I migrated a not working Server 2008 VM from the ESXi 5.5 U3 Host back to the other Host with ESXi 5.5 (2718055). > VM is reachable again. So VMotion again the to the "new" U3 one: > Network Problem is there again.
I do not tried to reboot the ESXi Host with 5.5 U3, to test that the Problem disappears with a reboot. Just because all the other vm's working without Problems.
Our Vmware License would allow me to open a Case at vmware. But at the Moment I just have no time for investigate this further.
I'm working with ESX since 2009 (Started in May 2009 with ESX 4.0 (164009). The ESXi 4.1 and 5.5. Vmotion Since 4.1.
But such a Problem I had never before during a Host Upgrade with update Manager.
At the End I just made an Bootbank-Rollback and have again 2 working servers.
http://vmwaremine.com/2012/03/30/how-to-roll-back-update-1-from-esxi5/
I hope you can understand my "German" English"