SSH, The Secure Shell: The Definitive Guide, 2nd Edition

Forwarding

SecureCRT supports the SSH feature called forwarding (Chapter 9), in which another network connection can be passed through SSH to encrypt it. It is also called tunneling because the SSH connection provides a secure “tunnel” through which another connection may pass. Both TCP port forwarding and X forwarding are supported. (As well as agent forwarding, as we mentioned earlier.)

17.5.1 Port Forwarding

Port forwarding permits an arbitrary TCP connection to be routed through an SSH connection, transparently encrypting its data. [9.2] This turns an insecure TCP connection, such as Telnet, IMAP, or NNTP (Usenet news), into a secure one. SecureCRT supports local port forwarding, meaning that your local SSH client (SecureCRT) forwards the connection to a remote SSH server.

Each SecureCRT session you create may have different port forwardings set up. To set up forwarding to a particular remote host, open the Session Options window and select Connection/Port Forwarding.

To create a new forwarding, first click the Add button to display the Local Port Forwarding Properties window, as in Figure 17-4. Then enter:

Name

Any descriptive name for your forwarding, to help you remember what it does.

Local

The port number on your local machine to connect to the secure tunnel. This can be just about any number, but for tradition’s sake, make it 1024 or higher. Choose a local port number that’s not being used by any other SSH client on your PC. If you want to restrict the local IP address that allows ...