Local forwarding is the act of mapping local TCP ports or Unix sockets onto remote ports or sockets. It's commonly used when either accessing a system securely (by requiring the user to first SSH to the box, thus encrypting their connection), or for troubleshooting problems.
In this section, we're going to start a small webserver on centos2, which we're going to connect to from centos1, first by connecting to the IP and port directly, and then by a connection to a mapped local port, utilizing port forwarding.