Use e2e for all communication you can

Thank you for such a long and detailed post! I indeed did not know about things beyond the SIM, and I didn’t know about the extra details about the country codes either. That is extremely interesting to me.

With the phone spoofing though, does that mean two factor with a phone number is basically useless? If I had authentication based on a MAC address, it would take seconds to break it. But I think, and sure hope, that auth based on phone numbers is more secure.

I think your domain name answer – that for the most part computers didnt need them – is a very satisfying answer.

no need for an endpoint to be directly exposed

If I were an engineer in the past, trying to send a message back to an endpoint (e.g. a server response) I would’ve reached for everything having a static IP, same as the EID system with phones, instead of the DHCP multi-tier NAT type system with temp addresses.

I’m all but certain they didnt do it for privacy reasons at the time.

I’m shocked this answer has so many upvotes. No, a MAC address is not close to a phone number. No two people have the same phone number, and I can’t just edit my phone number to be someone else’s number.

• “two network interfaces connected to two different networks can share the same MAC address”
• “Many network interfaces, however, support changing their MAC addresses”

https://en.m.wikipedia.org/wiki/MAC_address

Temple OS