The following two commands lets you rdp into a Windows insatnce that is on a private network via a linux jump host.
Run this command and then you have 30 seconds to establish an rdp session.
ssh -i private.key jumpbox@aa.bb.cc.dd.ee -fL 3389:172.12.1.10:3389 sleep 30
This will rdp into the private Windows instance at the other end of the ssh tunnel.
rdesktop 127.0.0.1 -u "Administrator" -r clipboard:PRIMARYCLIPBOARD -p "password,password" -g 1024x768