Report that there was a ``internet reset button'' on the plane

Engineer Robert Graham reported in X that ``there was a button to reset the Internet on the plane I boarded.''

Inflight wifi didn't work so of course I had to debug it. It appears the problem is lack of DHCP lease. The WiFi was using 8 hour leases, which was time enough for many planeloads of passengers to embark/disembark.

A quick ARP scan at the time showed there were 55 devices on the…

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— Robᵉʳᵗ Graham ???? (@ErrataRob) December 25, 2023

In order to be able to connect to the Internet on the plane he boarded, Mr. Graham signed a lease plan that allows him to connect to Wi-Fi for 8 hours. However, when he actually tried to connect to the in-flight Wi-Fi, it did not work.

Could this be because there are not enough IP addresses to lease with DHCP? Mr. Graham, who predicted that, performed an ARP scan to obtain the IP address and MAC address within the LAN. As a result, it was discovered that there were 55 devices on the plane's LAN, most of which were smartphones.

In fact, both iOS and Android have default specifications that randomize MAC addresses for the purpose of privacy protection, and even the same smartphone is assigned a new IP address every time it connects to Wi-Fi. Therefore, even if 55 devices are connected, the IP addresses that can be allocated for lease within 8 hours will be exhausted quickly.

According to Graham, even if the DHCP server runs out of IP addresses to allocate, no response is sent to the client, so it cannot be confirmed whether the lack of IP addresses is the cause of the wireless LAN becoming unusable. Still, while other people are assigned IP addresses from the DHCP server, he is the only one who is not, so Mr. Graham is unable to connect to the in-flight Wi-Fi because he is running out of IP addresses. I assumed that was the cause.

So, Mr. Graham told the flight attendant that ``Wi-Fi is not available,'' and the flight attendant pressed a button near the entrance and exit of the plane. According to flight attendants, they press that button every time a passenger complains that they can't connect to the internet.

When I looked closely at the button the flight attendant pressed, I saw that it said 'Internet Reset'. By pressing this button, the IP address assigned by the DHCP server will be released.

Mr. Graham suggests solutions to the problem of IP address depletion in in-flight Wi-Fi by ``drastically shortening IP address leases on airplanes, such as every hour,'' and ``drastically increasing the number of IP addresses that can be leased.'' ”.