It's easy to disable a VPN remotely though, especially on handheld devices.
All you need to is to point the user to a post or a website that is bloated with JS and contains high rez images and/or video.
The device then has to either begin paging memory like crazy - or more likely - begins to kill background processes that it thinks are not used by the foreground apps (e.g. your VPN).
For newer smartphones this is less of an issue, since their RAM can handle it. For > 5 year old smartphones though? They might struggle.
If you run a VPN app, you can use AFWall to force all traffic through the VPN. So if the VPN app isn't running for some reason, the apps set to only go through the VPN service will have no internet access.
Android has a VPN killswitch function since version 7 Nougat, which never fails. If your firewall/VPN gets killed in memory, your internet connection ceases to work until it is turned on and connected again.
Nowhere does that person say they used this option. These options appear when you hold tap VPN/firewall app you set in VPN settings.
Also, did they whitelist it from whatever battery saver phone has? Or disabled PowerGenie stuff? And used that little "keep app in memory" thing like this?
I force killed my both firewalls and this happened. The same stays when phone restarts until both firewalls are up and running.
I'm happy it works flawless for you man, and I'm sure on official Lineage builds which are as close as possible to AOSP things work exactly as you say.
I have an unofficial Lineage 18 ROM patched to hell to work with my old phone. All I can do is tell you what I see, and what I see is that when my phone tries to play a 720p or higher video, with an impossibly high bit-rate for the phone, the phone starts to aggressively background-kill apps, and that includes my VPN.
Again, happy it works for you, and I agree that in principle the default route should point to nothing if the VPN dies. On my device, when the virtual network device of the VPN goes down, it drops to the default network and finds another gateway.
I think then that is on whoever built/maintains that weird build of Lineage for your phone, and is definitely an anomaly. Maybe seek another good Android build, or if financially good, a new phone?
Sure, fair. Though I have enough phones I've collected over the years, I'm not sure if I need any more. As long as I take care not to go media heavy sites, my current device meets my needs almost all of the time.
Hmm, I’ve had that fail on some cheap Chinese phones. They have other software that kills things in the background irrespective of the setting. I developed a VPN client and was never truly able to solve this problem on some low memory devices.
The VPN may get killed, but the killswitch in network stack prevents any connection outside, unless you have some really weird noname phone with poorly developed custom Android build. If you have any brand phone you hear, Google, Huawei, Samsung, Xiaomi, Oppo, Vivo, Oneplus, Asus or any such big name, I do not think this issue will occur, atleast I have not heard or seen this on any decent budget specced device. Besides, I think having a device with less than 3-4 GB RAM is going to cause issues, because they are computers just in handheld form.