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 >>
    File Transfer Using SFTP >>
    File Transfer Using Transparent FTP Tunneling >>
    Tunneling on the Command Line >>
        Local Tunnels >>
        Remote Tunnels
            Examples of Remote Tunneling
        Tunneling FTP on the Command Line >>
        Agent Forwarding
    Troubleshooting SSH Tectia Server for IBM z/OS >>
    Advanced Information >>
    Man Pages >>
    Log Messages >>

Remote Tunnels

A remote (incoming) tunnel forwards traffic coming to a remote port to a specified local port.

With ssh2 on the command line, the syntax of the remote tunneling command is the following:

$ ssh2 -R [protocol/][listen-address:]listen-port:dst-host:dst-port server

Setting up remote tunneling allocates a listener port on the remote server. Whenever a connection is made to this listener, the connection is tunneled over Secure Shell to the local client and another connection is made from the client to a specified destination host and port. The connection from the client onwards will not be secure, it is a normal TCP connection.

Figure Remote tunneling terminology shows the different hosts and ports involved in remote port forwarding.


clientserver-tunnel-remote2-15.gif
Figure : Remote tunneling terminology

For example, if you issue the following command, all traffic which comes to port 1234 on the server will be forwarded to port 23 on the client. See Remote tunnel.

$ ssh2 -R 1234:localhost:23 username@sshserver

The forwarding address in the command is resolved at the (local) end point of the tunnel. In this case localhost refers to the client host.


clientserver-tunnel-remote-16.gif
Figure : Remote (incoming) tunnel

By default, the server allows remote tunnels from all addresses for all users. To restrict tunneling for all or for specified users, see Section Securing Tunneling.

Examples of Remote Tunneling

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