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Fixing 802.11w Deadlocks

G5 Cyber Security

TL;DR

The 802.11w deadlock issue, common with some wireless adapters and access points (APs), can cause devices to disconnect repeatedly. While a perfect fix doesn’t exist for *all* cases, several steps significantly improve stability. This guide covers disabling Protected Management Frames (PMF) where possible, updating firmware/drivers, checking AP settings, and considering alternative hardware.

Understanding the Problem

802.11w is a security feature designed to protect wireless management frames. However, some older or poorly implemented devices struggle with it, leading to constant disconnections and a ‘deadlock’ state where they repeatedly try to reconnect but fail. It’s often triggered by incompatibilities between the client device (laptop, phone) and the access point.

Solution Steps

  1. Disable Protected Management Frames (PMF) on the Access Point: This is usually the most effective solution.
    • Log into your access point’s administration interface. The address will vary depending on your AP manufacturer (e.g., 192.168.1.1, 192.168.0.1). Check your AP documentation if you’re unsure.
    • Navigate to the Wireless Security settings. Look for options related to ‘PMF’, ‘Protected Management Frames’, or ‘WPA3/WPA2-PSK with PMF’.
    • Set this option to Disabled, Optional, or Not Required (the exact wording depends on your AP). Avoid ‘Required’ if possible.
    • Save the changes and reboot the access point.
  2. Update Drivers & Firmware: Outdated software is a common cause of compatibility issues.
    • Wireless Adapter Driver: Update your laptop/device’s wireless adapter driver. In Windows, go to Device Manager (search for it in the Start Menu), expand ‘Network adapters’, right-click on your wireless adapter and select ‘Update driver’. Choose ‘Search automatically for drivers’.
    • Access Point Firmware: Check your access point manufacturer’s website for firmware updates. Download and install the latest version following their instructions. Be careful during this process as a failed update can brick your AP!
  3. Check Access Point Settings (Advanced): Some specific settings can interfere.
    • Channel Width: Try reducing the channel width from 40MHz to 20MHz. Wider channels are more prone to interference and compatibility issues.
    • Control Channel: If your AP allows it, manually set a control channel instead of using ‘Auto’. Experiment with different channels (1, 6, or 11 are often good choices).
    • DTIM Interval: Adjust the DTIM interval. A lower value (e.g., 1) can sometimes help but may increase network traffic. Start with a value of 3 and adjust if needed.
  4. Test with Different Client Devices: Determine if the issue is specific to one device.
    • If only one device experiences the problem, it’s likely an issue with that device’s adapter or driver.
    • If multiple devices are affected, the problem is more likely with the access point configuration.
  5. Consider Alternative Hardware: If all else fails, your hardware may be incompatible.
    • Try a different wireless adapter for your laptop/device. A USB Wi-Fi adapter can be a quick and easy test.
    • If the access point is old or known to have issues with 802.11w, consider replacing it with a newer model from a reputable manufacturer.
  6. Command Line Tools (Advanced – Linux): For Linux users, you can check wireless interface status. 
    iwconfig wlan0

    This command shows the current configuration of your wireless interface. Look for information about PMF support and encryption settings.

Important Notes

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