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Pawan Raut

ACI endpoint issue

I have connected the VMware on one of the leaf switches let say switch 6. I can see the endpoint mac address on leaf 6 from one of the physical ports but I don't see the mac address of that endpoint on leaf1 which is a border leaf connecting L2 external network.


what could be an issue any hint?

VIP Advocate

Hi @Pawan Raut 

You do not learn the Remote MAC because one of the two scenarios:

1. There is traffic with that SMC being sent to the border leaf

2. You have disabled the "Endpoint Data Plane Learning" on BD.


Of course, there is also the possibility to encounter a bug, but I would suggest first to verify scenario #1 or #2.


Stay safe,



Hi @Pawan Raut ,

I think Sergiu had the right answer in his head, but it got garbled (possibly auto-correct played a part too)

The two scenarios he suggested SHOULD have read:

  1. There is NO traffic with that MAC being sent to the border leaf
  2. You have disabled the "Endpoint Data Plane Learning" on BD.

Let me explain #1 a bit more - hopefully interpreting "I have connected the VMware on one of the leaf switches" correctly.

Firstly, I'll assume you mean that you have connected an ESXi Host to one of the leaf switches rather than the VMware vCenter management platform. (Sorry to be pedantic, but it matters)

Now that ESXi host will have a MAC address associated with the port that is connected - you rarely see any traffic from this MAC address, and if you do it is likely to be control packet of some kind such as an LACP multicast. You would not expect to see this MAC address on any other leaf because the ESXi host does not send traffic sourced with this MAC (unless it is assigned a vmk interface for say vmotion purposes)

The other (more likely) possibility is that you see MAC addresses that belong to the guest VMs that are hosted on that ESXi Host.  And this is where #1 really comes into play.

You will see the MAC address of that VM on the leaf that the VM is attached to, and any other leaf that if has layer 2 communication with - JUST LIKE ANY OTHER L2 topology - the difference being that that VM's broadcasts may not be flooded to (in your case) the border leaf.

So, what you need to investigate is whether the MAC address in question has any reason to communicate at layer2 with any device on the border leaf. If it doesn't, then you are seeing exactly what you should expect to see.


aka Chris Welsh

Don't forget to mark answers as correct if it solves your problem. This helps others find the correct answer if they search for the same problem

Hi Chris,

That's exactly what I wanted to write: "NO traffic with that MAC being sent to the border leaf". 

But I have an excuse for my typos: sometimes I think ahead of what I want to write and when I actually type I forgot some words, and also I have fat fingers