What Is vSphere Promiscuous Mode and How to Enable It

You probably known about the promiscuous mode. How about vSphere promiscuous mode? Do you know how to enable it if you need to monitor or troubleshoot? This article will show you walk you through it.


By Crystal / Updated on March 8, 2023

Share this: instagram reddit

What is vSphere promiscuous mode

You probably known about the promiscuous mode. In computer networking, promiscuous is a mode of operation, as well as a security, monitoring and administration technique. In fact, virtual networking supports promiscuous mode as well. For example, you can configure it on standard switch or distributed switch in vSphere.

vSphere promiscuous mode

vSphere promiscuous mode is a security policy which can be defined at the virtual switch or portgroup level in vSphere ESX/ESXi. A virtual machine, Service Console or VMkernel network interface in a portgroup which allows use of promiscuous mode can see all network traffic traversing the virtual switch.

Next, this article will introduce you what does vSphere promiscuous mode work and how to configure it.

How does vSphere promiscuous mode work

By default, a guest operating system's virtual network adapter only receives frames that are meant for it. Placing the guest's network adapter in VMware ESXi promiscuous mode causes it to receive all frames passed on the virtual switch on that host only that are allowed under the VLAN policy for the associated port group.

In a word, VMware ESXi promiscuous mode eliminates any reception filtering that the virtual machine adapter performs so that the guest operating system receives all traffic observed on the wire. This can be useful for intrusion detection monitoring or if a sniffer needs to analyze all traffic on the network segment.

Promiscuous mode reject

However, for software running inside a virtual machine may also be able to monitor any and all traffic moving across a vSwitch if it is allowed to enter promiscuous mode. Therefore, vSphere promiscuous mode is disabled by default, and should not be turned on unless specifically required.

If you need your vSphere enable promiscuous mode for legitimate reasons such as debugging, monitoring, or troubleshooting, you can refer to the following steps.

How to enable vSphere promiscuous mode

1. Log into the ESXi/ESX host or vCenter Server using the vSphere Client.

2. From the left inventory, click Networking.


3. From Port groups tab, select VM Network and click Actions > Edit settings.

edit settings

4. From the pop-up window, click Security to open the drop-down menu.

5. Here you can see Promiscuous mode option, select Accept and click Save.

Accept promiscuous mode

A dedicated vSphere backup software – AOMEI Cyber Backup

You may need an effective backup software for VMware vSphere to protect your virtual environment and gain the ability to quickly recover your virtual machines when needed. In this article, I will introduce an efficient vSphere backup software - AOMEI Cyber Backup, which enables you to backup multiple VMs either managed by vCenter Server, or on a standalone ESXi host.

It simplifies the backup process and present the steps with intuitive GUI interface. In addition, it offers you the following benefits.

Agentless Backup: create complete and independent image-level backup for VMware ESXi and Hyper-V VMs.
Flexible vSphere Backup: batch backup large numbers of VMs managed by vCenter Server, or multiple VMs on a standalone ESXi host.
Multiple Storage Destinations: backup to local drive, or network destinations like Windows share or NAS.
Automated Execution: create backup schedules to automate backups daily, weekly, monthly.
Role Assignment: allows one administrator to create sub-accounts with limited privileges.

AOMEI Cyber Backup

AOMEI Cyber Backup supports both paid and free versions of VMware ESXi 6.0 and later versions. Next, I will show you how to perform vSphere VM backup and restore via AOMEI Cyber Backup. You can click the following button to download the free trial.

Download Free TrialVMware ESXi & Hyper-V
Secure Download

*You can choose to install this VM backup software on either Windows or Linux system.

Steps to perform vSphere backup and restore via AOMEI Cyber Backup

Backup multiple VMs:

1. Bind Devices: Access to AOMEI Cyber Backup web client, navigate to Source Device > VMware > + Add VMware Device to Add vCenter or Standalone ESXi host. And then click > Bind Device.

Add VMware ESXi host

2. Create Backup Task: Navigate to Backup Task > + Create New Task, and select VMware ESXi Backup as the Backup Type.

VMware ESXi backup

3. Set the Task Name, Device, Target, Schedule and Cleanup as needed.

  • Task Name: you can change the task name or use the default name with an ordinal.
  • Device: batch backup multiple VMs on vCenter or standalone host within one backup task.

Select virtual machines vCenter

  • Target: select to back up to a local path, or to a network path like NAS.
  • Schedule (optional): perform full, differential, or incremental backup, and automate execution according to the frequency you specified.

Backup schedule type

  • Cleanup (optional): automatically delete the old backup copies that exceed the retention period you specified.

backup cleanup

4. Run Backup: Now you can click Start Backup and select Add the schedule and start backup now, or Add the schedule only.

Start Backup

Created backup tasks will be listed and monitored separately for restoring, progress checking and schedule changing.

Restore VM from backup:

5. Restore from Backup: Select the backup task you want to restore, and click ... > Restore to open the wizard.

Or you can click Backup Management > History Versions. Specify a VM and select a restore point from the left list.

Restire from backup task

6. Start Restore: Choose to Restore to original location or Restore to new location. And click Start Restore to recover the virtual machine in place.

Restore to new location: Create a new VM in the same or another datastore/host directly from the backup to perform out-of-spacre recovery, saves the trouble of re-configuring the new VM.

Restore to new location


vSphere promiscuous mode is a feature that enables observation of all network traffic traversing the virtual switch for debugging, monitoring, or troubleshooting purposes. This article briefly introduces how does it work and showed the steps how vSphere enable promiscuous mode from the web client.

In addition, to better secure your VM data, you’d better backup VMware ESXi VMs regularly. In this regard, AOMEI Cyber Backup is an efficient tool that you can try at an affordable price.

Crystal · Editor
Crystal is an editor from AOMEI Technology. She mainly writes articles about virtual machine. She is a positive young lady likes to share articles with peolpe. Off work she loves travelling and cooking which is wonderful for life.