what’s wrong with just texting
If you have friends in another country, it might cost a quarter every time you send a message.
In regions of the world (e.g. Europe, and a lot of Asia) where some countries are the size of a large city (or perhaps the entire country is one city), that’s a problem. You’d be sending international texts all day every day.
No. Any device that implements a certain DHCP feature is vulnerable. Linux doesn’t support it, because most Linux systems don’t even use DHCP at all let alone this edge case feature. And Android doesn’t support it because it inherited the Linux network stack.
I would bet some Linux systems are vulnerable, just not with the standard network packages installed. If you’re issued a Linux laptop for work, wouldn’t be surprised if it has a package that enables this feature. It essentially gives sysadmins more control over how packets are routed for every computer on the LAN.