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HP Virtual Connect and MAC Addresses

Trusted Contributor

HP Virtual Connect and MAC Addresses

Anthony had a question:




I’m looking for some information on how to potentially clear out some MAC addresses from a VC domain.  We have a blade that is in 1 VC domain, but it’s MAC is being registered in another VC domain.  So of course this renders the server useless.  Any help is appreciated, thanks.




Some discussion:




From Carl:

This would potentially cause problems with any future server profiles since the address ranges would have to be the same on both enclosures. 

You could have them try creating a new profile and leaving the old one unused, but that is just a workaround. They really need to rebuild the domain under a new address range.


From Dan:

Depends on where the root cause is.


If you used the same WWN Range on 2 domains, then you need to first fix that problem and then the easiest fix is to delete the profiles that were duplicates and re-create them. 

If the problem is that Windows captured the MAC Address from a profile in Domain A, and they moved the Server to Domain B and it kept the old MAC Addresses, then you can simply go into the HP Teaming Util (NCU) and reset the Virtual MAC Address which will use one of the MACs in the profile for the new Domain, letting go of the MAC from the old domain.


And from Robert:

I am not positive about what Anthony means when he says that the mac address is registered in another domain.  Virtual Connect mac address are associated with profiles, not the server hardware.  Unless there are two VC domains built with the same HP-Defined mac range, there should not be any duplicates. 


Mac addresses rarely get stuck.  They age out, typically after 300 seconds, if the source mac has not been seen in any header on any switch ports, or VC module.  If a mac is being learned in multiple locations in the network, it can be due to one of the following reasons. 


One is when administrators create a Windows build image after they have created a NIC team.  Then they use that image to build more Windows hosts.  When a NIC team is created, Windows records the team mac in the registry using one of the NIC hardware macs, and then on subsequent boots reads that team mac and overwrites the hardware mac addresses.  If a team was built on a system different than the NIC hardware, you can see this by examining the team ‘Settings’ tab in NCU.  You will see that the team mac and a default mac do not match.  Correct this by clicking the ‘Restore Default’ button. 


Another possibility is with ESXi.  Rather than rewrite the text, you may want to review this SAW article.  This is applicable when the VMware host management address is the one with a duplicate mac.




Any other comments or suggestions?