I am not sure if there is a solution to this problem, but every time I use the hotspot functionality, it is being detected by T-Mobile and subsequently my quota is getting quickly depleted. I was under the impression that GOS bypasses carrier restrictions of this kind, but apparently not. I find it hard to believe that I am the only one with this issue, so any help or advice would be appreciated!
What I have tried so far:

  1. Create a new APN and add the "dun" function.
  2. Try routing the hotspot traffic through VPN (less than ideal), but this is not supported on GOS.

    • [deleted]

    • Post #2
    • Edited

    They may be detecting it by packet inspection on their end which if that's the case not really anything that GOS can do about it.

    NoWayOut GrapheneOS does bypass these restrictions. Adding back dun would undo that. Raise TTL by 1 on the computer you're tethering and it won't be detected. The issue is that the TTL is 1 lower. This would also break container and VM setups within the OS with their own private networks unless they increased TTL by 1.

        GrapheneOS
        Thanks, but I had in mind more than a computer - basically wanted to use my phone as a portable router for multiple items.
        However, if this is not possible, just the computer would be fine, but I have no idea how to raise TTL on a Mac. This is what tried:

        sudo sysctl -w net.inet.ip.ttl=65
        sudo sysctl net.inet6.ip6.hlim=65

        But now the Mac now refuses to connect to the hotspot.

            a month later

            TTL was raised on my Mac using the following commands:

            sudo sysctl net.inet.ip.ttl=65
            sudo sysctl net.inet6.ip6.hlim=65

            Nothing changed, T-Mobile still detected hotspot usage. Super frustrating!!

              GrapheneOS Adding back dun would undo that. Raise TTL by 1 on the computer you're tethering and it won't be detected.

              This worked for me, also on T-Mobile.

                  NoWayOut I tried it couple of months ago on my laptop running Linux (openSUSE) and it worked. However, I never had to use it again.

                  I also did try it on Windows but that did not work.

                      ivicaivica
                      Thanks, my gut tells me that the carriers have closed this loophole for the "mass" operating systems. The CEO's of these carries belong behind bars, IMHO.

                          NoWayOut question for you: does the hotspot use a different APN then the default one? Does your macbook have same IP address as phone?
                          The internet reports that T-Mobile hotspot uses its own APN and that's how T-Mobile monitors data usage?

                              nrt
                              I only see the default APN. Not sure about the IP address, it never occurred to me to check, since I expected the damn thing to be plug and play. I am away from home now, but will check later.
                              The developers will do well to look at this. I know it is a low priority, but... it is not working as expected.

                                cgro0550 If you have a more plausible suggestion for it, say it.

                                https://en.wikipedia.org/wiki/TCP/IP_stack_fingerprinting
                                https://android.stackexchange.com/questions/47819/how-can-phone-companies-detect-tethering-incl-wifi-hotspot (note that the part about MAC addresses is arguably sort-of correct for IPv6 but probably wrong for IPv4)
                                https://ieeexplore.ieee.org/document/8958772
                                https://www.jitbit.com/alexblog/310-how-to-hide-tethering-from-your-mobile-operator/

                                • de0u replied to this.

                                    What seems to have been established so far is that increasing the TTL value by 1 does not
                                    work on Windows and MacOS. It appears to be working on Linux.

                                      NoWayOut What seems to have been established so far is that increasing the TTL value by 1 does not work on Windows and MacOS. It appears to be working on Linux.

                                      Two Linux kernels (Android and another one on a laptop) may well fingerprint the same way. If there is no TTL jitter then the tethering may go unnoticed. Windows, macOS, Plan 9, etc., may fingerprint very differently, in which case TTL tweaking by itself won't work.

                                      Meanwhile, I don't think my carrier has a "tethering quota", though I admit I haven't checked recently. Maybe switching carriers is an option?

                                        In the US, all the three big carriers do it.

                                        • de0u replied to this.

                                          NoWayOut pdanet+ or pairvpn, and you have to be doing something different be it an app, setting, configuration. I've never gotten notices even before I used GoS, although I was using apps mentioned above to mask it. Since GoS I don't bother with em.

                                          Using a Verizon MVNO Visible & UsMobile I've hit and blown past my cap on both plans with nothing more than GoS guilt in hotspotting. No issues.

                                              NoWayOut In the US, all the three big carriers do it.

                                              My carrier is Verizon. They write:

                                              Many of our monthly phone plans and certain prepaid plans let you use 5G Ultra Wideband, 5G and 4G LTE Mobile Hotspot on capable devices for no additional monthly charge.

                                              I looked at my "plan features" page and it says only:

                                              Personal Hotspot

                                              Use your shared data to turn your smartphone into a Wi-Fi connection for your other devices.

                                              So it's not clear to me that I have a tethering quota. They may have some plans with tethering limits, but that may be avoidable - on Verizon and maybe also on other carriers.

                                                NoWayOut Are you running a full system VPN on Windows? If you aren't, they can see you're connecting to Windows services and therefore must be running Windows. Raising the TTL by 1 and running a VPN should be adequate. You should verify that the TTL is being raised with the way you're configuring it.