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How to modify the mac address of vlan interface?

  • 1.  How to modify the mac address of vlan interface?

    Posted 08-12-2012 19:35

    Because different vlan interface have the same  mac address , how should I modiay the mac address of vlan interface?



  • 2.  RE: How to modify the mac address of vlan interface?

    Posted 08-14-2012 09:06

    Why would you want to modify the MAC address of the vlan interface? The vlans are located on the same switch, then they all are on the same physical device which means they should have the same physical MAC address. If you want to route traffic between the vlans, that is the purpose of the RVI interface to act as the gateway. The MAC address is physical(port and device), so what senario is prompting this requirement? Normally, I get upset when someone ask a question and the answer you get from responders, is why? The MAC address is meant to be unique and identify a device and or port. ALL must be unique. The only times I have seen where one wants to change the MAC address is spoofing.



  • 3.  RE: How to modify the mac address of vlan interface?

    Posted 08-14-2012 14:19

    As the switch is never plugged into itself, it doesn't matter whether the MAC addresses are the same or not and as far as other devices are concerned, they know to reach whatever destination, their MAC address table says to go to MAC addess xx.xx.xx and there will never be 2 MAC addresses on the same segment.

     

    If you do a "Show Chassis Mac-Address" it will show your base MAC address.  All MAC addresses come from this and from here the system allocates MAC addresses to interfaces.  There is a limit as to how many the system can allocate and some will be used internally by the switch, but you may find your MAC addresses are increasing by 1.

     

    In short, there should be no need to change these MAC addresses for your system to function normally, just configure the L3 addresses and your switch will just work.

     

     



  • 4.  RE: How to modify the mac address of vlan interface?

    Posted 08-21-2012 02:57

    Because different vlan interfaces have different mac address in H3C switch.

    Because my customer bought Ex4200 to replace H3C switch ,and they don't want to change topology.

    Because my English is very poor, so I can't explain why I need to modify the mac address of vlan interface exectly.
    But the answer is  "You can't modify the mac address of vian interface". Am I right?

     

    In some conditions, I can try to configure L3 interface to replace vlan interface, but sometimes I can't.



  • 5.  RE: How to modify the mac address of vlan interface?

    Posted 08-26-2012 15:40

    Understood. So the question is if you can explain the existing configuration on the H3C switches that you want to transfer to the EX4200. Maybe upload the config minus your personal internal information. You cannot enable "sticky mac" on Juniper switch, but you can enabe "persistent mac". I am saying that maybe what was accomplished on the H3C switch can be accomplished on the Juniper switch but a different way. I actually have not looked at the configuration to even note if the vlan interfaces are assigned a uniques MAC address, I understand better now. Any such MAC address would be automated by the system as Martin said. SO run this command "show interfaces extensive and look at the details of each of the rvi to see if they are assigned an individual unique MAC. Now whether you can modify it or not, I would defer to Juniper Engineers. Sorry I could not be of anymore help.



  • 6.  RE: How to modify the mac address of vlan interface?

    Posted 01-18-2019 01:55

    The valid excuse is when you do EVPN on QFX with Vlan Bundles your vlan l2 domains are smacked together. This makes it impossible to do router-on-a-stick with a SRX as EVPN has the additional requirement of unique MACs on ALL vlans per VNI.