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

# vlan(4)

IEEE 802.1Q and 802.1ad pseudo-device

## NAME

**vlan**, **svlan** – IEEE 802.1Q and 802.1ad pseudo-device

## SYNOPSIS

**pseudo-device vlan**

## DESCRIPTION

The **vlan** driver provides network interfaces supporting Virtual Local Area Networks (VLANs) on Ethernet networks. **vlan** interfaces implement virtual networks using the IEEE 802.1Q protocol. **svlan** interfaces implement virtual networks using the IEEE 802.1ad protocol.

**svlan** interfaces allow construction of IEEE 802.1ad-compliant provider bridges. **vlan** and **svlan** interfaces can be configured to provide QinQ or stacked VLANs.

The interfaces can be created at runtime using the **ifconfig** **vlan***N* **create** command or by setting up a [hostname.if(5)](/hostname.if/5.md) configuration file for [netstart(8)](/netstart/8.md). The interface itself can be configured with [ifconfig(8)](/ifconfig/8.md); see its manual page for more information.

**vlan** and **svlan** interfaces must be configured with a parent Ethernet interface to operate, and a virtual network identifier. Packets transmitted through a **vlan** or **svlan** interface will be encapsulated in their respective protocols and transmitted on the specified physical interface. 802.1Q and 802.1ad packets received on the parent interface will be matched to the **vlan** and **svlan** interfaces by their respective protocol and virtual network identifiers, and decapsulated for reception on the associated virtual interfaces.

The 802.1Q and 802.1ad protocols include a priority field. By default, the 802.1p priority in a transmitted packet is based on the priority of packets sent over the interface, which may be altered via [pf.conf(5)](/pf.conf/5.md); see the **prio** option for more information. Alternatively, **txprio** can set a specific priority for transmitted packets.

**vlan** and **svlan** interfaces support the following [ioctl(2)](/ioctl/2.md)s:

- SIOCSIFPARENT *struct if\_parent \**

  Set the parent interface. The parent may only be configured while the virtual interface is administratively down.

- SIOCGIFPARENT *struct if\_parent \**

  Get the currently configured parent interface.

- SIOCDIFPARENT *struct ifreq \**

  Delete the parent interface configuration. The parent may only be removed while the virtual interface is administratively down.

- SIOCSVNETID *struct ifreq \**

  Set the virtual network identifier. Valid identifiers are in the range 1 to 4094.

- SIOCGVNETID *struct ifreq \**

  Get the currently configured virtual network identifier.

- SIOCDVNETID *struct ifreq \**

  Clear the current virtual network identifier. Virtual interfaces without a configured virtual network identifier will use 0 in their protocols tag field.

- SIOCSIFLLADDR *struct ifreq \**

  Configure a custom MAC address on the virtual interface. When the virtual interface is using a custom MAC address, the parent interface will be configured to promiscuously receive packets. When operating without a custom MAC address, the virtual interface will inherit the parent interfaces MAC address. Configuring 00:00:00:00:00:00 as the MAC address will clear the custom MAC address configuration and resume operation with the parents MAC address.

**vlan** and **svlan** interfaces use the following capability on parent interfaces:

- IFCAP\_VLAN\_MTU

  The parent interface can handle full sized frames, plus the size of the vlan tag.

**vlan** interfaces use the following capability on parent interfaces:

- IFCAP\_VLAN\_HWTAGGING

  The parent interface will offload the encapsulation and decapsulation of 802.1Q frames.

## EXAMPLES

Create an 802.1Q virtual interface on top of the physical interface em0, with virtual network identifier 5:

```
# ifconfig vlan0 create
# ifconfig vlan0 parent em0 vnetid 5
# ifconfig vlan0 10.1.1.100/24
```

Create an 802.1Q VLAN interface on network 10, on top of an 802.1ad provider bridge on network 8, on top of the physical interface bge0:

```
# ifconfig svlan0 create
# ifconfig svlan0 parent bge0 vnetid 8
# ifconfig svlan0 up
# ifconfig vlan0 create
# ifconfig vlan0 parent svlan0 vnetid 10
# ifconfig vlan0 10.1.1.101/24
```

Configure an 802.1Q VLAN interface with a custom MAC address:

```
# ifconfig vlan0 lladdr fe:e1:ba:d0:84:0e
```

Remove a custom MAC address from an 802.1Q VLAN interface:

```
# ifconfig vlan0 lladdr 00:00:00:00:00:00
```

Force the use of priority 1 for transmitted packets, regardless of the packet priority:

```
# ifconfig vlan0 txprio 1
```

## SEE ALSO

[inet(4)](/inet/4.md), [ip(4)](/ip/4.md), [netintro(4)](/netintro/4.md), [hostname.if(5)](/hostname.if/5.md), [pf.conf(5)](/pf.conf/5.md), [ifconfig(8)](/ifconfig/8.md), [netstart(8)](/netstart/8.md)

## STANDARDS

*IEEE 802.1Q standard*, https://standards.ieee.org/standard/802\_1Q-2018.html.

*IEEE 802.1ad standard*, Provider Bridges, QinQ.

## AUTHORS

Originally Garrett Wollman ⟨*wollman@freebsd.org*⟩.

## CAVEATS

Some Ethernet chips will either discard or truncate Ethernet frames that are larger than 1514 bytes. This causes a problem as 802.1Q and 802.1ad tagged frames can be up to 1518 bytes. Most controller chips can be told not to discard large frames and/or to increase the allowed frame size.