BladeSystem Virtual Connect

NIC teaming and VC-assigned MAC address changing

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NIC teaming and VC-assigned MAC address changing

Vincent waa looking to resolve a customer issue:


Customer question below. Anybody reported that problem already ?


Currently we are using the HP pre-defined MAC address ranges setting in our environment and have had a few MAC address conflicts when moving the Blade server from one Enclosure to another and then populating the freed slot with a new blade server. The reason this is happening is because there are NICs teamed in the OS and when moving a blade with teamed NICs to another enclosure, the teaming configuration does not release the previous MAC address and this causes MAC address conflict when a new blade is installed in the free slot.


The only way to resolve this issue is by dissolving the team configuration and re-teaming again and this is causing other issues and the management has now decided to use the factory default MAC address rather than the pre-defined. Do you know of any fixes from either HP or Microsoft that can make the NIC teaming to use the new pre-defined  MAC address rather than retain the old MAC address.


Herman weighed in on the subject:


I’ve seen this before in various incarnations.  As you have indicated below, when you team NICs with our teaming driver it selects one of the team members’ burnt-in MAC addresses (in this case the VC assigned MAC address will be the burnt-in MAC address from the OS perspective)  to use as the team MAC address.  This team MAC address is retained as long as the team exists even if the NIC hardware changes via system board replacement, OS image transfer, or even if the VC Assigned MAC Addresses change.


Dissolving and re-creating the team is one method to get a new team MAC address.


A less drastic method, although it still requires manual intervention, is to go to the HP NCU, highlight the team, go to Settings and click the restore default button.  This will cause the team to get a new team MAC address from one of the current team members.  There is a place to locally administer the team MAC Address there too so maybe the new MAC address can be pre-provisioned prior to the move to another enclosure (just a thought).



Other comments or suggestions? Have you had this problem? If so, how did you resolve it?