A few static MACs among a sea of auto-generated

[taylorb]

I have hundreds of VMs and I have never made any of them static.   Now our network team has purchased a solution from a vendor that requires a handful of VMs with static MAC addresses.  They are creating the VMs for us and want these MAC addresses beforehand.     I am at a loss for how to find and reserve a handful of MACs that I can use for this without using a duplicate or using an address that VMware might hand out in the future.    The only KB articles I can find on this list incorrect information.  

Any ideas?  I tried arbitrary MACs but it breaks networking.  The MAC has to start with 00:05:56 or routing is hosed.  And that is the same prefix that the auto MACs start with by default. 

[a_p_]

Which KB article do you refer to?

According to e.g. http://kb.vmware.com/kb/219 a manually MAC address can be anything between 00:50:56:00:00:00 and 00:50:56:3F:FF:FF.

André

[taylorb]

Thanks, but that article is the incorrect one I was referring to.  It states that 00:50:56 are for manual and 00:0C:29 is for Auto.  But that is not (or no longer) true.   Auto generated MACs also use 00:50:56 as per the Vsphere 5 manual:  http://pubs.vmware.com/vsphere-50/topic/com.vmware.vsphere.networking.doc_50/GUID-1C9C9FA5-2D2D-48DA...

So the range for possible static and auto is the same.  And there isn't a way I can see to reserve or see the used addresses.

[taylorb]

We decided that the very top of the address range would be unlikely to be used, so we decided to use the last few addresses prior to 00:05:56:3F:FF:FF.  We checked the arp table on our physical switch and nothing close to that address was in there, so I think that should work.

It would be nice if there was a better way to manage this other than guessing and checking resources outside Vmware, however.

[a_p_ · Accepted solution]

It states that 00:50:56 are for manual and 00:0C:29 is for Auto ...

Basically yes, but only MAC addresses above 00:50:56:3F:FF:FF are automatically assigned, so you should not have any issues with manually assigning addresses between 00:50:56:00:00:00 and 00:50:56:3F:FF:FF.

André

[taylorb]

That's not true.    The range above 05:50:56:3F:FF:FF is used with VMware Workstation and other Vmware product. 

The auto MAC on a VM I just created starts with 05:50:56:AC

[a_p_]

The range above 05:50:56:3F:FF:FF is used with VMware Workstation and other Vmware product.

That's correct and that's why you need to configure a static MAC address below 05:50:56:3F:FF:FF.

André

[taylorb]

That's what I did, but I was just pointing out that the auto generated addresses are in that same range - below 3F:FF:FF. 

According to the documentation I have been reading, VMware will be not use an address you have statically assigned when it auto assigns in the future.  But you could run into problems if you statically assign a MAC that is already being used by a running VM.   There about 4 million possibilities, so the odds are slim, but I still wish there was at least a good way to see MACs in use or something like that.

[a_p_]

That's what I did, but I was just pointing out that the auto generated addresses are in that same range - below 3F:FF:FF.

Do you have VM's within this range? Which VMware product has been used in this case?

At least the MAC address you posted (05:50:56:AC) is above this range.

André

[taylorb]

Man, here I am arguing with you like you are being thick and you are totally right.

Somehow I was thinking AC < 3F.   Now that I look back at it, all the 00:05:56 MACs I can find on the switch are above 3F.

Thanks for sticking with me until the lightbulb came on!