Added new packet format P_DATA_V2, which includes peer-id. If server
supports, client sends all data packets in the new format. When data
packet arrives, server identifies peer by peer-id. If peer's ip/port has
changed, server assumes that client has floated, verifies HMAC and
updates ip/port in
It looks like on Windows, OpenVPN ignores the MTU it's supposed to be
using and just queries the TAP driver for its MTU.
I suspect this was done in the past because there was no way to *set*
the MTU that Windows was expected to use.
That is no longer the case; recent versions of Windows let you
