Change mac-address on Vlan

[orekom]

Hi!!

Is it possibly to change the mac-address on a vlan interface? When i use the command "(config-if) mac-address H.H.H" i change the mac-address for all the vlan interfaces. I´m using C6509 running native IOS

[jbayuka]

No, it is not possible. As far as i know, it is an implementation restriction. But I do not see any real purpose to have them differently. Do you have any specific requirement? If so, can you explain in detail.

[rpeasah]

I'm not the originator of this thread but I've a need to change macs on VLANs on a 6509. I've a situation here where all the mac-addresses for all the VLANS (20 of them) on the 6509 are the same. I tried changing them and giving each VLAN a unique mac. Unfortunately, whatever mac I put in last becomes the mac for all the VLANS. I've talked others who've seen the same thing on 6509s and they were able to manually change the macs. I guess I may have to run this by TAC.

[phil.benn]

Hi,

I'm curious about this one. Can you explain in what situation you would need different macs for each Vlan interface, as the MACs are only significant in that VLAN.

Thanks.

[pingduck]

This is a very old topic but it came up top in google search. So I would add some opinions.

Normally, there is no need to change the MAC for a VLAN interface because VLANs are basically separated LAN and their MAC address will not matter. But someone need to modify the VLAN interface, there is usually done to workaround some other issues or some creative ways of using network interfaces that could benefit from having the ability to control VLAN interface MAC.

For example, maybe someone need physically loop back 2 switch ports in order to impose a specific feature order. The 2 interfaces has the same MAC and will have trouble switching packet. 

It maybe hard for someone to agree it makes sense to change the VLAN i/f MAC. This mainly because he did not have to spend days to workaround a bug or undocumented feature. Sometime it might be the simplest way to get things done. A more flexible device would go a long way. If VLAN interface's MAC cannot be changed, it is best to have the config option removed to avoid any false hope.

[dducamps01]

on  C6504

System image file is "bootdisk:s2t54-ipservicesk9-mz.SPA.154-1.SY4.bin"

it is possible to change independantly MAC-adress of an interface vlan

[Nico Declerck]

Some providers refuse to give you an IP address with the MAC address of known router manufacturers. e.g. Telenet in Belgium 

They want you to upgrade to a more expensive account.