---
name: "rtwn"
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/rtwn"
---

# rtwn(4)

Realtek RTL8188CE/RTL8188EE/RTL8192CE/RTL8723AE PCIe IEEE 802.11b/g/n wireless network device

## NAME

**rtwn** – Realtek RTL8188CE/RTL8188EE/RTL8192CE/RTL8723AE PCIe IEEE 802.11b/g/n wireless network device

## SYNOPSIS

**rtwn\* at pci? port ?**

## DESCRIPTION

The **rtwn** driver supports PCIe wireless network devices based on the Realtek RTL8188CE, RTL8188EE, RTL8192CE and RTL8723AE chipsets.

The RTL8188CE, RTL8188EE and RTL8723AE are highly integrated 802.11n adapters that combine a MAC, a 1T1R capable baseband and an RF in a single chip. The RTL8723AE also includes a Bluetooth 2.1/3.0/4.0 controller.

The RTL8192CE is a highly integrated multiple-in, multiple-out (MIMO) 802.11n adapter that combines a MAC, a 2T2R capable baseband and an RF in a single chip.

These devices operate in the 2GHz spectrum only.

These are the modes the **rtwn** driver can operate in:

- BSS mode

  Also known as *infrastructure* mode, this is used when associating with an access point, through which all traffic passes. This mode is the default.

- monitor mode

  In this mode the driver is able to receive packets without associating with an access point. This disables the internal receive filter and enables the card to capture packets from networks which it wouldn't normally have access to, or to scan for access points.

The **rtwn** driver can be configured to use Wired Equivalent Privacy (WEP) or Wi-Fi Protected Access (WPA1 and WPA2). WPA2 is currently the most secure encryption standard for wireless networks supported by OpenBSD. It is strongly recommended that neither WEP nor WPA1 are used as the sole mechanism to secure wireless communication, due to serious weaknesses. WPA1 is disabled by default and may be enabled using the option "**wpaprotos** *wpa1,wpa2*". For standard WPA networks which use pre-shared keys (PSK), keys are configured using the "**wpakey**" option. WPA-Enterprise networks require use of the wpa\_supplicant package.

The **rtwn** driver can be configured at runtime with [ifconfig(8)](/ifconfig/8.md) or on boot with [hostname.if(5)](/hostname.if/5.md).

## FILES

The adapter needs firmware files to run, which are loaded on demand by the driver when the device is attached:

- */etc/firmware/rtwn-rtl8188e*

  - */etc/firmware/rtwn-rtl8192cU*

  - */etc/firmware/rtwn-rtl8192cU\_B*

  - */etc/firmware/rtwn-rtl8723*

  - */etc/firmware/rtwn-rtl8723\_B*

  ## EXAMPLES

The following example scans for available networks:

```
# ifconfig rtwn0 scan
```

The following [hostname.if(5)](/hostname.if/5.md) example configures rtwn0 to join network “mynwid”, using WPA key “mywpakey”, obtaining an IP address using DHCP:

```
join mynwid wpakey mywpakey
inet autoconf
```

## DIAGNOSTICS

- rtwn0: could not read firmware ...

  For some reason, the driver was unable to read the microcode file from the filesystem. The file might be missing or corrupted.

- rtwn0: device timeout

  A frame dispatched to the hardware for transmission did not complete in time. The driver will reset the hardware. This should not happen.

## SEE ALSO

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

## HISTORY

The **rtwn** driver first appeared in OpenBSD 5.8.

## AUTHORS

The **rtwn** driver was written by Stefan Sperling ⟨*stsp@openbsd.org*⟩. It was based on the [urtwn(4)](/urtwn/4.md) driver written by Damien Bergamini ⟨*damien.bergamini@free.fr*⟩.

## CAVEATS

The **rtwn** driver does not support any of the 802.11n capabilities offered by the adapters. Additional work is required in [ieee80211(9)](/ieee80211/9.md) before those features can be supported.