VmWare static MAC question on VM

Posted on 2009-02-17
Medium Priority
Last Modified: 2012-06-21
We have one VM that had some networking issues this past weekend.  We fixed the problem by vmotioning the server from host1 to host4. Host1 shows no issues or NIC problems. However, the one exception about this VM is that it is assigned a static MAC address inside Windows. That was done originally to solve an application licensing issue when we originally P2V'd it. My question, is that every now(and other VM's that are on the same host as this VM) and then we have issues with this VM and losing network packets, etc.  Could having a static MAC address inside Windows(it was the MAC originally from the physical) cause some sort of routing issues? The VM Nic itself has a VmWare assigned MAC address, but the OS has a different MAC. If so, how can we fix?
Question by:alaskannative
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LVL 21

Expert Comment

ID: 23664074
You would need to probably modify your VMX file with the MAC address that you use. That could help.
Don't know if you use ESX / Virtual Center, but the following link will show you how  even if you are using VMWare server. .
LVL 21

Accepted Solution

za_mkh earned 750 total points
ID: 23664163
I know this is a stupid solution, but actually due to the limitation of the static MAC address mappings, your statIc MAC address for a VM guest must normally start with the OUI assigned to VMWare being: 00:50:56.
So overriding the MAC from within the GUEST is probably causing a conflict with the VMWare network driver hence the loss of packets.
So a potential solution is... can you ask your vendor to generate a new licence file based on the MAC address that is in the VMWare Range.
The link in my previous post still holds about configuring a 'static' MAC..

Author Comment

ID: 23665548
Actually, that is a good solution, but for this particular server, the app owner doesn't know what exactly is tied to the MAC address. All he knows is that when we dynamically assign one, it breaks IIS and other FTP jobs. So, its not like a traditional licensing to MAC address problem. Even if I gave him a static MAC in the VmWare range, he wouldn't know where to configure it to keep the app or FTP jobs from bombing.  
LVL 21

Expert Comment

ID: 23668654
Ah that's fantastic! Hopefully the installed software (add/remove programs list) on the server would be a clue as to what it could be? Or browsing the IIS websites installed on the server could hopefully narrow it down...

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