---
name: "vmx"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["freebsd", "openbsd"]
url: "https://new.carta.tech/vmx"
---

# vmx(4)

VMware VMXNET3 Virtual Interface Controller device

## NAME

**vmx** – VMware VMXNET3 Virtual Interface Controller device

## SYNOPSIS

**vmx\*** **at** **pci?**

## DESCRIPTION

The **vmx** driver provides support for the VMXNET3 virtual NIC available in virtual machines by VMware. It appears as a simple Ethernet device but is actually a virtual network interface to the underlying host operating system.

This driver supports the **VMXNET3** driver protocol, as an alternative to the emulated [pcn(4)](/pcn/4.md), [em(4)](/em/4.md) and the earlier VMXNET [vic(4)](/vic/4.md) interfaces also available in the VMware environment. The **vmx** driver is optimized for the virtual machine, it can provide advanced capabilities depending on the underlying host operating system and the physical network interface controller of the host. In comparison to the earlier VMXNET versions, as supported by the [vic(4)](/vic/4.md) driver, VMXNET3 supports additional features like multiqueue support, IPv6 checksum offloading, MSI/MSI-X support and hardware VLAN tagging in VMware's VLAN Guest Tagging (VGT) mode.

The **vmx** driver supports VMXNET3 VMware virtual NICs provided by the virtual machine hardware version 7 or newer, as provided by the following products:

- VMware ESX/ESXi 4.0 and newer

- VMware Server 2.0 and newer

- VMware Workstation 6.5 and newer

- VMware Fusion 2.0 and newer

The **vmx** driver supports the following media types:

- autoselect

  Enable autoselection of the media type and options. The driver always uses the fastest available speed and the media options provided by the underlying host of the virtual machine.

- 10GbaseT mediaopt full-duplex

  Set 10Gbps operation.

- 1000baseT mediaopt full-duplex

  Set 1000Mbps operation.

For more information on configuring this device, see [ifconfig(8)](/ifconfig/8.md).

## EXAMPLES

The following entry must be added to the VMware configuration file to provide the **vmx** device:

```
ethernet0.virtualDev = "vmxnet3"
```

## SEE ALSO

[arp(4)](/arp/4.md), [em(4)](/em/4.md), [ifmedia(4)](/ifmedia/4.md), [intro(4)](/intro/4.md), [netintro(4)](/netintro/4.md), [pci(4)](/pci/4.md), [pcn(4)](/pcn/4.md), [vic(4)](/vic/4.md), [hostname.if(5)](/hostname.if/5.md), [ifconfig(8)](/ifconfig/8.md)

## HISTORY

The **vmx** driver first appeared in OpenBSD 5.5.

## AUTHORS

The **vmx** driver was written by Tsubai Masanari.