I have a remote PC (behind NAT and firewall) set up to create a reverse SSH tunnel to my home PC/server (DMZed). Unfortunately, the tunnel hasn't been working lately. Fortunately -- I think -- the remote PC currently has an SFTP session open to the local one. My question is, can I create a tunnel back to the remote PC through that session? Or am I SOL until I can physically get in to restore the reverse tunnel on the remote PC?