Network Connectivity Issues with Virtual Network Adapters in Promiscuous Mode

Products

• VMware vSphere ESXi

Issue/Introduction

I'm running a network sniffer inside the guest operating system or have an application, service, or driver that puts my virtual network adapter into promiscuous mode.

I see one or more of the following symptoms in the guest operating system:

• My virtual machine does not reply to multicast or broadcast pings.
• My guest operating system is not receiving ARP requests. I'm not able to ping the virtual machine from a different machine. I can ping from my virtual machine to another machine. Once I ping another machine from the virtual machine, I can ping the virtual machine.
• My guest operating system is not receiving a DHCP response from the DHCP server or is unable to renew a DHCP lease.
• The DHCP server on my virtual machine is not receiving DHCP requests and is not leasing IP addresses.
• The sniffer doesn't detect any broadcast or multicast packets.

What is causing these problems?

Environment

VMware ESX Server 2.5.x
VMware ESX Server 3.0.x
VMware ESX 4.1.x
VMware ESXi 3.5.x Embedded
VMware ESX Server 2.0.x
VMware ESX Server 3.5.x
VMware ESX Server 2.1.x
VMware ESX 4.0.x
VMware ESXi 3.5.x Installable
VMware ESXi 4.0.x Embedded
VMware ESXi 4.0.x Installable
VMware ESXi 4.1.x Installable
VMware ESXi 4.1.x Embedded

Resolution

If you run a network packet sniffer or other application inside the guest operating system that puts the virtual network adapter into promiscuous mode, your guest operating system may not receive multicast and broadcast frames if you do not have the virtual switch configured in promiscuous mode.

To use a virtual network adapter in promiscuous mode, you must also put the virtual switch to which it connects in promiscuous mode. For more information, see Configuring promiscuous mode on a virtual switch or portgroup (1004099).

Note: In the guest operating system, bring down and bring back up the virtual network adapter to have the changes take effect. If your virtual machine is running Windows NT 4, you must reboot the virtual machine.