* Responding to three way handshake before the other end actually does
(nmap -sT remote host ends up with every port being 'open' but closing
connection right away)
This is the action of the TCP accelerator. TCP has a "long fat pipe" problem where high-delay links (like a trip to geostationary orbit and back) demolish throughput. To combat this, satellite protocols translate TCP flows to a non-TCP or modified TCP protocol for transmission through the satellite and then back to TCP in the modem.
Regards,
Bill Herrin
--