Well said. Perimeter security controls such as firewalls are so 20th century. Defense in depth and individual device risk assessments right up through the OSI stack and beyond are the only modern best practices. Trust is an often misunderstood word and single points of failure (misconfiguration, yet to be publicised vulnerabilities, and just plain wrong assumptions) kill kittens and invalidate the expense of deploying security controls in the first place.

shine brightly, .vortex

Indeed, in fact IIRC there were IP over SMS experiments done in earlier GSM network days - when SMS was seen as more of a free test function than the profitable social phenomenon it is today. As were IP over SMTP mail headers of store-and-forward networks such as UUCP or FidoNet - sure latency was horrific, but as an obscure side channel it was workable. What irks me is that in modern times byte-for-byte SMS is often quoted as one of the most expensive forms of digital transmission, so to quote it as an appropriate channel for developing nations seems a little weird.

shine, .vortex