Show HN: eBPF Based Unlimited Hotspot for Android(github.com)
github.com
Show HN: eBPF Based Unlimited Hotspot for Android
https://github.com/i64/ebpf-stuff/tree/main/android/ttl_increment
2 comments
I had ChatGPT explain why this is works as a unlimited hotpot. Very cool: "It works because carriers detect tethering partly by looking at TTL values. Android subtracts 1 from TTL when hotspot/tethering packets are forwarded, so the carrier sees a different TTL and knows the traffic came from a tethered device.
Your eBPF program increments the TTL back by +1, hiding the fact that the packet was forwarded through your phone. So to the carrier, the traffic looks like it originated directly from the phone, not from a tethered device. That defeats one of the carrier’s tethering-detection methods."
in normal you would do use this trick. but however new phones does not include the kernel module that helps you to modify the TTL using iptables
iptables -t mangle -A PREROUTING -i "$INTERFACE" -j TTL --ttl-inc 1
iptables -t mangle -I POSTROUTING -o "$INTERFACE" -j TTL --ttl-inc 1