About Setting Up Port Forwarding

When you use Connectivity Secure Shell to set up any type of port forwarding, what you are doing is creating a Secure Shell tunnel, thereby providing a safer route for network traffic, and then directing the traffic so that it automatically assumes this detour.

Before endeavouring to set up an outgoing or incoming port forwarding, it will help to take a closer conceptual look at the mechanics of directing network traffic in this manner. As its name implies, port forwarding depends largely on port configuration for this task.

Normally, a POP server on remote host listens for connections on the default TCP port (110).

In an example of an outgoing port forwarding, the connection occurs as follows:

1. The e-mail client on the workstation sends a connection request to a local port instead of port 110 on the server. For the purpose of this example, we can specify port 3800.
2. The Connectivity Secure Shell tunnel you created must be configured to listen on local port 3800. When it receives the data, the connectivity Secure Shell engine encrypts it and sends it through the Secure Shell tunnel to the Secure Shell server on Host B.
3. After it is decrypted by the Secure Shell server, the data arrives at the destination port, 110, just as it would have were it not secured in transit. After the TCP connection is established through the Secure Shell tunnel, data returned by the POP server follows the same path in reverse.