T-Mobile custom APN settings didn't help me and neither did the latest update. I use NordVPN WireGuard, but switching to OpenVPN doesn't help either.

T-Mobile doesn't work via IPv4 at all in my area. If I use custom APN settings and select IPv4 or IPv4/IPv6, then I don't get any data conneciton regardless of VPN Lockdown usage. Exclusive IPv6 is the only functional APN setting for me that allows for data to work...

I wish I knew more about the issue. There is a commit for it that describes eBPF changes, but that's too advanced for me. It has something to do with how VPN Lockdown setting treats inbound traffic on IPv6 networks.

At least in my case, I get a good stable connection once I enable Airplane mode, disable VPN Lockdown, disable Airplane mode, connect to VPN, and re-enable VPN lockdown.

I'm curious to know whether Google is aware of this issue and is actually planning to fix it? Has Google even confirmed awareness of this problem?

I'd like to alert T-Mobile, Google, and VPN providers about this issue, but have no idea how to get to the right level of tech support and what information to provide. It has to be something specific network engineers can work with.

Has the latest (October 2022) update fixed this issue for anyone? It didn't do so for me and Google didn't mention anything about it in its release notes. I doubt Google is ever going to fix this problem.

This issue is big enough for almost all my clients to want to either downgrade to Android 12 or move to a different carrier that doesn't use IPv6 or at least doesn't use IPv6 exclusively.

    8 days later

    I think it is possible that Google simply isn't going to fix this issue... The positive side is that this problem makes VPN Lockdown more restrictive compared to VPN Lockdown that offers exceptions for affected 464XLAT networks.

    Fhggyy5767 Yeah, most unfortunate. Makes the device practically unusable for me. Worked for a while after disabling the option "stop running in the background if not active" but broke again after a while.

      DesktopCloneLanguage have you tried using Open VPN for Android and downloading manual configurations from your provider? That's the app I'm using. It gives you lots of control like split tunneling but will shut off all connections when your data usage reaches a minimal level and the screen is off. Your phone and text still work until you turn the screen back on. This is a shot in the dark but it is the app I'm using with manual Nord configurations downloaded

        Fhggyy5767

        This issue, supposedly, only affects a small number of people, which is why fixing it is not a priority for Google. Its considered an "Upstream" issue and is to be resolved by Google, not GrapheneOS.

          OpenSource-Ghost

          Fhggyy5767

          I'm surprised that this fix worked for me when I was having the same problem as everyone else. Makes me think the fix "upstream" shouldn't be that tuff for google. Also, why does my brother with the same phone and service but not on GOS not having this problem? Now, I didn't just say it's a problem with GOS. I'm just curious why it's so random that we have the same device, share VPN provider account and he didn't have to do anything to get his VPN up and running setup exactly like mine. Such a random, strange issue for few.

          Three1989

          1. Turn off block connection's without VPN.
          2. Toggle airplane mode.
          3. Connect to VPN
          4. Go back to settings and turn "block connection's without VPN" back on

            Fhggyy5767

            Even that doesn't get me to connect to MobileData w/VPN. I've been no-VPN since getting my 6a onto Graphene. WiFI+VPN works fine. The workaround did work, briefly (5min or so) right when A13 was released, but no longer.

            TMobile (40000000018.7) + Mullvad + 6a + GOS 1016build

            ... AlwaysOnVPN set to NO (so block-connections option is greyed-out/ isn't an option)

            ... sure would like to find that the upstream issue were trackable. Being on mobile data is > half of my use, and I don't take measures like running Graphene to walk around without a VPN.

              Three1989 Sorry to hear that. It drives me crazy having this problem. It sucks listening to Spotify or doing anything for that matter that needs data and it shuts off and has to be reset. I don't understand how Google could make a feature like this and then send it out broken. I'm blown away by this broken feature.