How to Use iwlist in Linux: Get Detailed Wireless Interface Information Easily

The iwlist command in Linux provides detailed information about a wireless network interface, making it an essential tool for managing and troubleshooting wireless connections. It can be used to list available networks, their signal strength, encryption protocols, and more. This blog will walk you through using iwlist to retrieve and understand detailed wireless information.

What is iwlist?

iwlist is part of the wireless tools package in Linux. It is used to extract detailed information about a wireless interface, such as available access points, their signal strengths, supported encryption methods, and frequency. While iwconfig provides basic information, iwlist offers more granular details.

How to Use iwlist

Before using iwlist, you need to have the root user privileges, as gathering detailed wireless data often requires administrative access.

1. Check Available Wireless Interfaces:
   First, determine the name of your wireless interface (e.g., wlan0, wlp3s0) by using the following command:

   iwconfig

2. Get Detailed Scan Information:
   To scan and list the available networks near you, run:

   sudo iwlist wlan0 scan

Replace wlan0 with the actual interface name. This command will output information about nearby wireless networks.

Example Output Breakdown

Here’s an example of the output from sudo iwlist wlan0 scan:

Cell 01 - Address: AA:BB:CC:DD:EE:FF
          ESSID:"Network1"
          Mode:Master
          Frequency:2.437 GHz (Channel 6)
          Quality=70/100  Signal level=-50 dBm  
          Encryption key:on
          WPA2
          Bit Rates:54 Mb/s

• Cell 01: Each detected network is identified by a “Cell” number.
• Address: The MAC address of the access point.
• ESSID: The name of the network (SSID).
• Frequency: The operating frequency and channel of the access point.
• Signal Quality: Indicates signal strength, with Signal level showing power in dBm (the higher, the better).
• Encryption: Shows if encryption is enabled (WPA, WPA2, etc.).

Other Useful Commands with iwlist

• Frequency List: To see all supported frequencies of the interface:

  sudo iwlist wlan0 frequency

• Channel List: To list the channels the wireless interface supports:

  sudo iwlist wlan0 channel

• Bit Rate Information: To get available bit rates:

  sudo iwlist wlan0 bitrate

Troubleshooting with iwlist

iwlist is highly useful for troubleshooting wireless connectivity issues. For example, if you’re facing weak signal issues, you can use the scan option to check the signal strength of available networks. If encryption settings are incorrect, the output will show the encryption type, helping you identify misconfigurations.