Ssh reverse tunnel
From Teknologisk videncenter
To ssh to a host behind a firewall that doesn't allow incoming connections, a reverse ssh tunnel can be created from the server to a known client host. The client host should have a static IP address or a DNS hostname.
Remote server
To allow login without password create public/private rsa key pair and
ssh -o TCPKeepAlive=yes -R 9000:localhost:22 heth@93.166.84.21