iw

iw is a command-line tool used for configuring and managing wireless devices in Linux. It supports the modern nl80211 interface and is intended to replace older tools like iwconfig. The iw command provides more advanced and detailed control over wireless interfaces and supports the latest features of wireless hardware.

Basic Usage

To use iw, you typically need root privileges. The general syntax of the iw command is:

iw [OPTIONS] COMMAND [COMMAND_OPTIONS]

Common Commands and Options

List Devices

List all wireless devices:
```
iw dev
```

Example output:

phy#0
   Interface wlan0
       ifindex 3
       wdev 0x1
       addr 00:11:22:33:44:55
       type managed
       txpower 20.00 dBm

Link Status

Show information about the current link:
```
iw dev wlan0 link
```

Example output:

Connected to 00:11:22:33:44:55 (on wlan0)
SSID: MyNetwork
freq: 2412
RX: 1234567 bytes (2345 packets)
TX: 987654 bytes (3456 packets)
signal: -40 dBm
tx bitrate: 54.0 MBit/s

Scan for Networks

Scan for available wireless networks:
```
iw dev wlan0 scan
```

Example output:

BSS 00:11:22:33:44:55(on wlan0)
   TSF: 123456789012 usec (0d, 12:34:56)
   freq: 2412
   beacon interval: 100 TUs
   capability: ESS (0x0421)
   signal: -40 dBm
   last seen: 50 ms ago
   SSID: MyNetwork
   Supported rates: 1.0 2.0 5.5 11.0 22.0 36.0 48.0 54.0
   DS Parameter set: channel 1
   RSN:     * Version: 1
           * Group cipher: CCMP
           * Pairwise ciphers: CCMP
           * Authentication suites: PSK
           * Capabilities: 16-PTKSA-RC 1-GTKSA-RC (0x0000)

Set Interface Down
- Bring a wireless interface down:
  iw dev wlan0 set type managed
- Example:
  ip link set wlan0 down
Set Interface Up
- Bring a wireless interface up:
  iw dev wlan0 set type managed
- Example:
  ip link set wlan0 up
Join a Network
- Connect to a wireless network (requires WPA supplicant for encrypted networks):
  iw dev wlan0 connect MyNetwork
- For encrypted networks, additional configuration with WPA supplicant or network manager is needed.
Disconnect from a Network
- Disconnect from the current network:
  iw dev wlan0 disconnect
Set Wireless Power Save Mode
- Enable power save mode:
  iw dev wlan0 set power_save on
- Disable power save mode:
  iw dev wlan0 set power_save off
Show Station Information
- Show information about connected stations (for access points):
  iw dev wlan0 station dump
Change Wireless Interface Type
- Change the type of a wireless interface (e.g., from managed to monitor):
  iw dev wlan0 set type monitor

Example Configuration Workflow

List Available Wireless Interfaces
```
iw dev
```
Bring the Interface Down
```
ip link set wlan0 down
```
Set Interface Type
```
iw dev wlan0 set type managed
```
Bring the Interface Up
```
ip link set wlan0 up
```
Scan for Available Networks
```
iw dev wlan0 scan
```
Connect to a Network
```
iw dev wlan0 connect MyNetwork
```

Conclusion

The iw tool is a powerful utility for managing and configuring wireless devices in Linux. It provides comprehensive control over wireless interfaces and supports advanced features. By mastering iw, administrators can effectively manage wireless connectivity and troubleshoot issues.

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Last updated 6 months ago