[nanliu]

During my last visit using GoogleFI, the mobile phone shows a US IP when running whatismyip. So even though the phone is connected to the local telecom 5G network, traffic is segmented and routed back to the US carrier (T-Mobile in AWS US east IP ranges if I remember correctly) before hitting any website. So phones with GoogleFI sim works like a US client with a bit higher latency. This was really nice, but attempting to tether another device to the phone was a highly frustrating exercise as it did not work reliably whatsoever.

[nneonneo]

Google Fi, along with many other mobile telecoms, tend to limit the speed that you can attain from tethering, especially when roaming. Since computers don’t usually expect this, programs tend to misbehave on such metered connections.

In fact, I built a tool to specifically circumvent this: https://github.com/nneonneo/iOS-SOCKS-Server. It provides a SOCKS proxy through which you can tunnel any TCP connection, and have the connection appear to originate from your phone (and thus not be subject to the tethering rate limit). I used this when I was in China recently (2019).