In this chapter, we discussed SSH port forwarding and X forwarding.
Port forwarding is a general TCP proxying feature that tunnels TCP
connections through an SSH session. This is useful for securing
otherwise insecure protocols running on top of TCP or for tunneling
TCP connections through firewalls that would otherwise forbid access.
X forwarding is a special case of port forwarding for X Window System
connections, for which SSH has extra support. This makes it easy to
secure X connections with SSH, which is good because X, while popular
and useful, is notoriously insecure. Access control on forwarded
ports is normally coarse, but you can achieve finer control with the
9.4. Forwarding Security: TCP-wrappers and libwrap