SSH Tectia 
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    About This Document >>
    Installing SSH Tectia Server for IBM z/OS >>
    Getting Started with SSH Tectia Server for IBM z/OS >>
    Configuring the Server >>
    Configuring the Client >>
    Authentication >>
    Transferring Files >>
    Tunneling >>
        Local Tunnels >>
        Remote Tunnels >>
        Tunneling FTP
            Tunneling FTP in Passive Mode
            Tunneling FTP in Active Mode
            Examples of FTP Tunneling
        Agent Forwarding
    Troubleshooting SSH Tectia Server for IBM z/OS >>
    Advanced Information >>
    Man Pages >>
    Log Messages >>

Tunneling FTP

With SSH Tectia Server and Client, it is possible to easily forward FTP connections by using a command with the following syntax:

$ ssh2 -L ftp/x:ftpdserver:y username@sshserver

FTP tunneling is an extension to the generic tunneling mechanism. The FTP control channel can be secured by using generic port forwarding, but since the FTP protocol requires creating separate TCP connections for the files to be transferred, all the files would be transferred unencrypted when using generic port forwarding, as these separate TCP connections would not be forwarded automatically.

To protect also the transferred files, use FTP forwarding instead. It works similarly to generic port forwarding, except that the FTP forwarding code monitors the forwarded FTP control channel and dynamically creates new port forwardings for the data channels as they are requested. To see exactly how this is done, two different cases need to be examined: the active mode and the passive mode of the FTP protocol.

Tunneling FTP in Passive Mode

Tunneling FTP in Active Mode

Examples of FTP Tunneling

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