[Anunayj]

For someone more curious, I tried to learn more about this tech, and this [1] is the best resource I found about someone explaining how it works.

Essentially VoWifi connects to your ISP via a IPSec VPN using secrets derived using your sim card as a smart card, then connects to a internal SIP server and voila.

I spent a lot of time trying to connect to the IPSec server from a computer, but couldn't figure out how to get the challenge solved by my sim. Gosh I wish I could make normal calls from my computer.

1. https://worthdoingbadly.com/vowifi/

[egwynn]

Thanks for this link! This is a great explanation which clears a lot of things up to me.