This will allow connection to the remote machine based upon RSA authentication instead of passwords. 10.10.7 SSH Tunneling OpenSSH has the ability to create a tunnel to encapsulate another protocol in an encrypted session. Forces ssh to use version 2 of the protocol. Indicates no command, or tunnel only. If omitted, ssh would initiate a normal session.
Forces ssh to run in the background.
The remote SSH server. An SSH tunnel works by creating a listen socket on localhost on the specified port. In the example, port 5023 on localhost is being forwarded to port 23 on localhost of the remote machine. Since 23 is telnet, this would create a secure telnet session through an SSH tunnel. This can be used to wrap any number of insecure TCP protocols such as smtp, pop3, ftp, etc.