On 24/01/2019 00:45, Biggles wrote:
Internet mail between servers uses SMTP which isn't
encrypted.

pretty sure it can be and routinely is. But not universally.

Viz TLS and friends.


--
Future generations will wonder in bemused amazement that the early
twenty-first centurys developed world went into hysterical panic over a
globally average temperature increase of a few tenths of a degree, and,
on the basis of gross exaggerations of highly uncertain computer
projections combined into implausible chains of inference, proceeded to
contemplate a rollback of the industrial age.

Richard Lindzen