#on internet facing machine:
NON_INTERNET_MACHINE=192.168.1.164
ssh -v -L 5000:$NON_INTERNET_MACHINE:5000 tunnel@$NON_INTERNET_MACHINE -g
mkfifo /tmp/windows7-rdp-fifo
nc -l -u 4000 < /tmp/windows7-rdp-fifo | nc localhost 5000 > /tmp/windows7-rdp-fifo

#on machine with rdp server on port 4000
NON_INTERNET_MACHINE=192.168.1.164
nc -l 5000 < /tmp/windows7-rdp-fifo | nc -u $NON_INTERNET_MACHINE 4000 > /tmp/windows7-rdp-fifo