"SSH is a versatile protocol and OpenSSH, a versatile tool
— so much so, that it can be used for a lot of extremely cool
things. Throw in netcat, another Swiss Army Knife networking tool
that is even more all-purpose than SSH (in terms of networking
capabilities), and you get the network versatility of netcat with
the strong encryption and authentication of SSH.
"One of the best uses for netcat and SSH is to create a
transparent SSH tunnel through a secure bastion host. This
essentially means that you connect to a secure host in order to
reach another host, using the bastion host as a transparent
middle-man. There are a number of reasons to require something like
this. The most common, by far, is a locked-down SSH server that
restricts access to all but a few known IPs, usually via
tcp_wrapper rules or firewall rules."