How to use the command 'iwlist' (with examples)

The iwlist command is a powerful tool in the Linux environment used for getting detailed information from a wireless network interface. This command can interact with wireless interfaces to display a wealth of information about networks in range, supported frequencies and bitrates, encryption keys, power management settings, and more. While iwlist is often invoked by network administrators and power users, anyone interested in low-level operations of their Wi-Fi network can find it useful.

Display the list of access points and ad-hoc cells in range

Code:

iwlist wireless_interface scan

Motivation:

Knowing which wireless access points and ad-hoc cells are within range helps users and network administrators understand the density and availability of networks in an area. This information can help in making decisions about which network to connect to, especially if signal strength or network congestion is a concern.

Explanation:

• iwlist: This is the command that lets you list wireless interface information.
• wireless_interface: Substitute this placeholder with your actual wireless interface identifier, like wlan0 or wlp2s0.
• scan: This argument instructs iwlist to scan the area for available wireless networks, listing all detected access points and ad-hoc networks.

Example Output:

wlan0     Scan completed :
          Cell 01 - Address: 00:14:22:01:23:45
                    ESSID:"Home_Network"
                    Signal level=70/100
          Cell 02 - Address: 00:14:BF:11:09:45
                    ESSID:"Cafe_WiFi"
                    Signal level=65/100

Display available frequencies in the device

Code:

iwlist wireless_interface frequency

Motivation:

Understanding which frequencies a device can operate on is crucial for configuring networks efficiently and resolving connectivity issues. Different frequencies can affect network reach and penetration through physical barriers, thus selecting the optimal frequency can enhance the connection quality.

Explanation:

• iwlist: This command is used for gathering detailed information from a wireless interface.
• wireless_interface: Replace this with your specific wireless interface like wlan0.
• frequency: This tells iwlist to display the frequencies on which the device is capable of operating.

Example Output:

wlan0     13 channels in total; available frequencies:
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          ...
          Channel 13 : 2.472 GHz

List the bit-rates supported by the device

Code:

iwlist wireless_interface rate

Motivation:

Identifying the supported bit-rates helps users understand the potential data transmission speeds available on the device. This is essential for troubleshooting network speed issues and ensuring optimal configuration for high-speed data transfers.

Explanation:

• iwlist: The command used to get detailed wireless information.
• wireless_interface: Substitute with your wireless interface name such as wlan0.
• rate: This argument instructs iwlist to list the bit-rates that the device can use.

Example Output:

wlan0     Supported Bit Rates: 1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s

List the WPA authentication parameters currently set

Code:

iwlist wireless_interface auth

Motivation:

Displaying current WPA authentication parameters helps in ensuring that the device uses the appropriate standards for secure connections. This is vital for maintaining secure communications over a wireless medium, especially in public or enterprise environments.

Explanation:

• iwlist: Command to access detailed wireless information.
• wireless_interface: Replace with the actual wireless interface like wlan0.
• auth: This argument queries the device for its current WPA authentication settings.

Example Output:

wlan0     Authentication suites (1) : PSK
          Preauthentication Supported

List all the WPA encryption keys set in the device

Code:

iwlist wireless_interface wpakeys

Motivation:

Retrieving encryption keys allows users to verify configuration security, providing insight into potential vulnerabilities if any keys are weak, missing, or improperly set. This helps in managing and improving the overall security framework in wireless networks.

Explanation:

• iwlist: The command employed for acquiring detailed wireless interface data.
• wireless_interface: Input your specific wireless interface, such as wlan0.
• wpakeys: This argument lists all the set WPA encryption keys on the device.

Example Output:

wlan0     WPA Authentication IEEE 802.11i:
          Key:0   [1]   <no key>
          Key:1   [2]   <no key>

List the encryption key sizes supported and all encryption keys set in the device

Code:

iwlist wireless_interface keys

Motivation:

Understanding which encryption keys and sizes are supported aids in network security audits and configuration validation, ensuring that robust encryption standards are upheld in wireless communications to protect sensitive data.

Explanation:

• iwlist: This command is used to probe wireless interface details.
• wireless_interface: Use your wireless interface identifier, i.e., wlan0.
• keys: This argument provides a listing of supported encryption key sizes and any existing keys on your device.

Example Output:

wlan0     Encryption key:off
          Current Transmit Key: key disabled
          Security mode:open

List the various power management attributes and modes of the device

Code:

iwlist wireless_interface power

Motivation:

Power management settings are crucial when optimizing battery life versus performance in mobile and portable devices. This information can guide users in configuring their devices for better energy efficiency without sacrificing network responsiveness.

Explanation:

• iwlist: The command used to extract detailed wireless interface information.
• wireless_interface: Substitute with the particular interface name, such as wlan0.
• power: This argument lists the power management modes and attributes available.

Example Output:

wlan0     Power Management:off
          Mode:All packets received
          Timeout:0ms

List generic information elements set in the device (used for WPA support)

Code:

iwlist wireless_interface genie

Motivation:

Generic information elements provide a more in-depth look at the parameters and configurations influencing WPA support, assisting in thorough diagnostics and optimization of security protocols in use.

Explanation:

• iwlist: The command for querying detailed information from a wireless interface.
• wireless_interface: Replace with the appropriate wireless interface name like wlan0.

Example Output:

wlan0     Generic Information elements:
          Element ID: 221, Length: 26
          OUI: 00-50-f2, Data: 01-01-00-50-f2-02-01-0C-00

Conclusion:

The iwlist command is an indomitable tool in managing and scrutinizing Wi-Fi interfaces and their associated parameters in Linux environments. Its diverse use cases—from listing nearby access points to reviewing key security settings and frequencies—are invaluable for administrators and security-conscious users in maintaining efficient and secure networks. Through an understanding of its various arguments, users can optimize wireless settings to better suit their personalized environment and needs.