Pekka Riikonen writes:
> The window at the remote peer will move to 31000; no replay errors.

That is true for outgoing packets. That is not possible for the
incoming packets, as attacker can replay packets sent to you just
before it caused you to crash, thus causing those replayed packets to
get through. 

> The issue is only with outbound sequence numbers, because as we know, the 
> window can move always forward with incoming packets.  So even if the 
> incoming window is lagging behind it will always move forward when the 
> remote sends new packets to us.

But before there is any packets from the real peer having bigger
sequence numbers, the attacker can send old replayed packets from time
before crash, and cause those replayed packets to be accepted.

In most cases this does not matter, but in some environments it might
be very important that such replayed messages are not forwarded.
-- 
kivi...@iki.fi
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