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URTW(4) Device Drivers Manual URTW(4)

urtwRealtek RTL8187L/RTL8187B USB IEEE 802.11b/g wireless network device

urtw* at uhub? port ?

The urtw driver supports USB 802.11b/g wireless adapters based on the Realtek RTL8187L and RTL8187B.

These are the modes the urtw driver can operate in:

BSS mode
Also known as 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 urtw driver can be configured to use Wired Equivalent Privacy (WEP) or Wi-Fi Protected Access (WPA-PSK and WPA2-PSK). WPA is the current encryption standard for wireless networks. It is strongly recommended that WEP not be used as the sole mechanism to secure wireless communication, due to serious weaknesses in it. The urtw driver relies on the software 802.11 stack for both encryption and decryption of data frames.

The urtw driver can be configured at runtime with ifconfig(8) or on boot with hostname.if(5).

The following adapters should work:

Alfa AWUS036H
ASUS P5B Deluxe
Belkin F5D7050E
Linksys WUSB54GC v2
Netgear WG111v2
Netgear WG111v3
Shuttle XPC Accessory PN20
Sitecom WL-168 v1
Sitecom WL-168 v4
Surecom EP-9001-g rev 2A
TRENDnet TEW-424UB V3.xR

The following example scans for available networks:

# ifconfig urtw0 scan

The following hostname.if(5) example configures urtw0 to join network “mynwid”, using WPA key “mywpakey”, obtaining an IP address using DHCP:

nwid mynwid
wpakey mywpakey

arp(4), ifmedia(4), intro(4), netintro(4), usb(4), hostname.if(5), hostapd(8), ifconfig(8)

Realtek Semiconductor:

The urtw device driver first appeared in OpenBSD 4.5.

The urtw driver was written by Weongyo Jeong <>.

February 15, 2014 OpenBSD-5.6