Port Forwarding

Port forwarding, also known as tunneling, provides a way to redirect communications through the Secure Shell channel of an active session. When port forwarding is configured, all data sent to a specified port is redirected through the secure channel. You can configure any of the following.

Local port forwarding moves data securely between an application client running on the Secure Shell client host and a remote application server.
Remote port forwarding moves data securely between an application client running on the Secure Shell server host and a local application server.
FTP forwarding allows you to forward all FTP communications through the Secure Shell tunnel.
X11 forwarding moves X protocol data securely between an X server running on the Secure Shell client host and an X client running on the Secure Shell server host. This is a special category of dynamic remote port forwarding, and is configured using different settings.

Terminology

Port forwarding involves two sets of client and server applications — the Secure Shell client and server, and the client/server pair whose data is being forwarded. In this guide, the following terms are used as defined below in reference to port forwarding:

Term	Definition
Secure Shell server	The Reflection for Secure IT server daemon.
Secure Shell server host	The computer on which the Secure Shell server runs.
Secure Shell client	The Reflection for Secure IT client application.
Secure Shell client host	The computer on which the Secure Shell client runs.
Application client	The client program of the client/server pair whose data you want to forward. For example, this might be a mail client or Web browser.
Application client host	The computer on which the application client runs. This is often either the Secure Shell server host or the Secure Shell client host, but it can also be a third host.
Application server	The server program that communicates with your application client, such as a mail server or Web server.
Application server host	The computer on which the server application runs. This can be either the Secure Shell server host or the Secure Shell client host, or it can also be a third host.

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