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Air Marshal WiFi blocking (whitelisting, WiFi Direct names, blocking detection)

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  • Air Marshal WiFi blocking (whitelisting, WiFi Direct names, blocking detection)

    FYI for teams having WiFi Direct problems:

    The WiFi Direct connection between our RC and DS phones was behaving erratically - frequent disconnects, short range, periods where they wouldn't connect at all. These same phones worked flawlessly last season. It turns out our school updated its network and WiFi equipment, which now includes the use of Cisco Meraki's Air Marshal. Air Marhsal is supposed to detect rogue APs - wireless access points plugged into the school LAN without permission - and prevent them from functioning properly. In theory, our WiFi Direct connections shouldn't be affected as they are not associated with the school's wired LAN, but turning off Air Marshal allowed the phones to connect and function normally (big thanks to our IT department for their cooperation).

    The Air Marshal software allows certain connections to be whitelisted, which can be done by SSID name or MAC address. Whitelisting our SSID was problematic as Android adds random characters to the WiFi Direct name that will change whenever the wireless group is "forgotten" and a new connection between the RC and DS is made.

    If your phones won't pair/connect properly, or if they are already paired and don't connect anymore, this could be the cause. Try moving away from any wireless networks to see if the problem clears up.

    FTC App developers - it may be helpful to add these features to the FTC Apps:

    1) Detection of spoofed "deauth" packets by the RC app to alert users that WiFi blocking is taking place.
    2) Elimination of the random characters in SSID names to make whitelisting easier.

    The top answer in this thread may be helpful for #2: https://stackoverflow.com/questions/...adcast-an-ssid


  • #2
    Now that is interesting if this kind of wifi blocking is installed in school where competition held

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    • #3
      Originally posted by BayBuilder View Post
      FYI for teams having WiFi Direct problems:

      The WiFi Direct connection between our RC and DS phones was behaving erratically - frequent disconnects, short range, periods where they wouldn't connect at all. These same phones worked flawlessly last season. It turns out our school updated its network and WiFi equipment, which now includes the use of Cisco Meraki's Air Marshal. Air Marhsal is supposed to detect rogue APs - wireless access points plugged into the school LAN without permission - and prevent them from functioning properly. In theory, our WiFi Direct connections shouldn't be affected as they are not associated with the school's wired LAN, but turning off Air Marshal allowed the phones to connect and function normally (big thanks to our IT department for their cooperation).

      The Air Marshal software allows certain connections to be whitelisted, which can be done by SSID name or MAC address. Whitelisting our SSID was problematic as Android adds random characters to the WiFi Direct name that will change whenever the wireless group is "forgotten" and a new connection between the RC and DS is made.

      If your phones won't pair/connect properly, or if they are already paired and don't connect anymore, this could be the cause. Try moving away from any wireless networks to see if the problem clears up.

      FTC App developers - it may be helpful to add these features to the FTC Apps:

      1) Detection of spoofed "deauth" packets by the RC app to alert users that WiFi blocking is taking place.
      2) Elimination of the random characters in SSID names to make whitelisting easier.

      The top answer in this thread may be helpful for #2: https://stackoverflow.com/questions/...adcast-an-ssid
      Hi BayBuilder,

      Thanks for the feedback and suggestions...

      1. Unfortunately, I don't think the FTC apps are able to detect the spoofed "DEAUTH" packets, but we regularly use other methods (specifically Wireshark/PCAP running on a Linux or Mac computer) to monitor the spectrum at large events to look for suspicious DEAUTH packets and other network issues on the spectrum.
      2. Unfortunately, the random characters in the SSID names are auto-generated by Android's Wi-Fi Direct/P2P technology. This makes it difficult to authorize a Wi-Fi Direct connection on a "white list". Wi-Fi Direct was intended to allow devices to connect, ad-hoc, to each other. The Wi-Fi Direct group name (its SSID) is auto generated and can change arbitrarily. For example, if the group owner (in our case the Robot Controller) changes the operating Wi-Fi channel, I believe that the SSID can also change.

      In general, Wi-Fi blockers/suppressors will disrupt the FTC control system (it also will disrupt the FRC control system, so the problem is not limited to our technology). FIRST recommends that these suppressors be disabled during a competition or during practice.

      Also, it's important to note that the FCC ruled that Wi-Fi blocking is prohibited:

      https://www.fcc.gov/document/warning...ing-prohibited

      I hope this info helps. Thanks again for the feedback and information.

      Tom

      Comment


      • #4
        We had this exact problem at our scrimmage last month. Only a few teams were affected but it kept them from competing. We had our phones whitelisted afterward but it didn't fix the problem for long. We are going to try whitelisting using the MAC instead to see if that works better. It's doubtful that my school will want to disable the blocker.

        Joanne

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