It's not "stuff you can fix in the protocol itself" so much as "things a really smart proxy can do" -- with different levels, basically "a stateless proxy with

It's not "stuff you can fix in the protocol itself" so much as "things a really smart proxy can do" -- with different levels, basically "a stateless proxy with no real specific information about your client or server other than what is well-known", "a slightly-stateful proxy which can learn", "a fully stateful proxy", "a logging proxy which just has to identify threats retrospectively and alarm, rather than block".