Summary
- Once learned, a MAC address is never aged out. For very long running ESX VMs with high churn in used MAC addresses (e.g. via nested guest VMs) this may be a problem. If the MAC table of a particular port is full, the MAC learning functionality can no longer improve performance.
- MAC learning is not applied to multicast traffic and multicast traffic will see no performance improvement.
Requirements
- vSphere ESXi 5.x & ESXi 6.x
Instructions
For more details, you can refer to this blog post by William Lam
Installation consists of two parts:
- Download and install the VIB on all ESXi hosts:
esx-dvfilter-maclearn-6.5.0.vib
vmware-esx-dvfilter-maclearn-1.0.vib - Activate the functionality on a per VM basis
1. To install the VIB, you can run the following ESXCLI command if you have uploaded the VIB to an ESXi datastore:
esxcli software vib install -v /vmfs/volumes/[DATASTORE-NAME]/vmware-esx-dvfilter-maclearn-0.1-ESX-5.0.vib -f
A system reboot is not necessary and you can confirm the dvFilter was successfully installed by running the following command:
/sbin/summarize-dvfilter
You should see the dvfilter-maclearn module loaded as seen in the screenshot below:
2. For the dvFilter to work, you will need to add two Advanced Virtual Machine Settings to each of your Nested ESXi VMs. This setting is on a per vNIC basis, which means you will need to add N-entries if you have N-vNICs on your Nested ESXi VM.
ethernet0.filter4.name=dvfilter-maclearn
ethernet0.filter4.onFailure=failOpen
This configuration can be performed online without rebooting the Nested ESXi VMs if you leverage the vSphere API. Another way to add this is to shutdown your Nested ESXi VM and use either the “legacy” vSphere C# Client or vSphere Web Client or for those that know how to append and reload the .VMX file as that’s where the configuration file is persisted on disk.
If you normally provision Nested ESXi VMs with 2 vNICs, you will have two corresponding entries. To confirm the settings are loaded, we can re-run the summarize-dvfilter command and we should now see our Virtual Machine listed in the output along with each vNIC instance.
Changelog
Version 2.0
- New VIB to support ESXi 6.5
Version 1.0
- Supports ESXi 5.x and 6.0
Contributors
Similar Flings
No similar flings found. Check these out instead...

App Volumes Packaging Utility
This App Volumes Packaging Utility helps to package applications. With this fling, packagers can add the necessary metadata to MSIX app attach VHDs so they can be used alongside existing AV format packages.

Workspace ONE UEM Profile Migration Utility
The Workspace ONE UEM Profile Migration Utility aides in moving Profiles between Workspace ONE UEM Consoles.

Jenkins Plugin for CodeStream
This open source Jenkins plugin Fling integrates VMware vRealize CodeStream with Jenkins.

Android vSphere Big Data Extensions Client
Android vSphere Big Data Extensions Client is an Android application which provides vSphere BDE users a tool for monitoring and simple management of the vSphere BDE server.

Rollcall
Rollcall is an application that is used to provision Users and Groups from Google Workspace or Azure Active Directory to Workspace ONE Access.

vSAN Hardware Compatibility List Checker
The VSAN Hardware Compatibility List Checker is a tool that verifies all installed storage adapters against the VSAN supported storage controller list.