======SSH Tricks======

=====Reverse ssh tunnel=====
Set "GatewayPorts yes" in /etc/ssh/sshd_config on the server.

On client (behind NAT):
<code>
ssh -R 6333:localhost:22 server_user@server
</code>
Leave this connection open.

On server (public accessible):
<code>
ssh client_user@localhost -p 6333
</code>

Now the server is connected to the client.

=====Port forwarding=====
On client type the following
<code>
ssh -f user@server -L 2000:server:25 -N
</code>
It will make it possible to connect to port 25 on the server via port 2000 on the client.\\
Removing '-f' will stop ssh from going to the background.