Unix HOW-TO

This portion of the HOW-TO is intended to give instructions on setting up and using port forwarding on a Unix workstation.

• Computer Systems Lab Documentation
  • 2 HOW-TOs and Other Advanced Documentation
    • 2.2 HOW-TO use SSH to establish a remote connection and transfer files
      • 2.2.1 Unix HOW-TO
        • 2.2.1.1 Getting and installing SSH for Unix systems
        • 2.2.1.2 Setting up port forwarding on Unix
        • 2.2.1.3 Transferring files from my home Unix workstation to my CS account
        • 2.2.1.4 Reading POP mail from a home Unix workstation using SSH

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2.2.1.1 Getting and installing SSH for Unix systems

SSH is already installed on all CSL Unix workstations. If you need to install SSH on another Unix system, a free Unix implementation of SSH is available for non-commercial use from: ftp://ftp.funet.fi/pub/unix/security/login/ssh. Get the lastest version 1.x (not version 2.x -- for AFS, Kerberos and SecureCRT compatability reasons, we are currently using version 1.x of ssh).

For more information on using the Unix SSH package, please see the manual pages included in the package.

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2.2.1.2 Setting up port forwarding on Unix

1. Start an SSH session, specifiying the local and remote ports:
   
   % ssh -L local-port:remote-host:remote-port remote-port remote-host
   
   
   • local-port should be either the starndard port (if not otherwise in use) or an ununsed port number above 49152.
   • remote-port should be the standard port number. A list of available ports and their designations can be found in /etc/services
   • remost-host should be the name of the remote computer
   
   
2. Start the client application, using localhost for remote-host, and the applicable local-port

Note: Users can establish a secure connection with any unix-based Computer Science computer they are authorized to log into.

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2.2.1.3 Transferring files from my home Unix workstation to my CS account

% ssh -L 21:route66.cs.wisc.edu:21 route66.cs.wisc.edu

% ftp route66.cs.wisc.edu

• This uses port forwarding to establish a secure connection (via SSH) to route66, then establishes an FTP session to it.
• It IS necessary to specify remote-host instead of using localhost (localhost was specified in setting up port forwarding).
• Port 21 is the port designated in /etc/services as the ftp port.
• remote-host is any Unix-based Computer Science computer you are authorized to log into. Simply replace route66.cs.wisc.edu with the appropriate hostname.

Note: Users can establish a secure connection with any unix-based Computer Science computer they are authorized to log into. Simply replace route66.cs.wisc.edu with the appropriate hostname.

See Also:

Setting up port forwarding on Unix

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2.2.1.4 Reading POP mail from a home Unix workstation using SSH

1. To securely read your mail from a POP server, use SSH to establish a secure telnet session.
2. Use a textbased email program such as pine or mh (both are supported mail clients) to access your email account.

Note: Users who receive email on a particular workstation should use that workstation name as the remost-host when setting up the secure telnet session.

See Also:

Setting up port forwarding on Unix

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