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TN3270 Plus SSH Support

TN3270 Plus release 4.0.0 and above support SSH Version 2. SSH support is included with the TN3270 Plus SSH Feature. You must include the SSH Feature in your order if you require SSH support. If you currently have TN3270 Plus without the SSH Feature, you can order an upgrade and add the SSH Feature. A typical TN3270 Plus configuration for an SSH connection to a Unix host computer would include:

Telnet Base
VT/ANSI Terminal
SSH Feature

Please see TN3270 Plus Prices page for complete details and volume discount information. 

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Activating SSH support after you install TN3270 Plus

See Connecting to a Host Computer using SSH for instructions on how to set up your SSH connection. If you have still have questions, please e-mail for prompt assistance.



TN3270 Plus is an SSH client. It can be used to connect to an SSH server via TCP/IP. Most Unix-based operating systems run SSH server software and allow SSH client connections. The SSH (Secure Shell) protocol was developed to replace telnet, rlogin and rsh (Remote Shell) protocols that did not encrypt communications between client and host. SSH allows the secure transmission of data across the Internet. TN3270 Plus SSH allows a secure connection to a host computer. Data transmitted to and from the host computer is safe from viewing and tampering by outside parties.

Security Considerations

SSH version 1 is considered obsolete. The SSH version 1 design contains some inherent flaws that make it vulnerable to "man-in-the-middle" attacks.  SSH version 1 support has been removed in TN3270 Plus release 4.0.0 and above. Although TN3270 Plus releases earlier than release 4.0.0 support SSH version 1, it is recommended that SSH version 2 be used instead of SSH version 1 unless there is no other option. TN3270 Plus release 3.7.4 is available to users until they convert from SSH version 1 to SSH version 2.

Additional Information

For additional information and greater detail about how SSH works, see the following links:

  • Wikipedia: Secure Shell - Details about the Secure Shell (SSH) protocol.

  • SSH Communication Security - The company founded by Tatu Ylönen, the designer of SSH-1 the first version of the SSH protocol. SSH Communications markets proprietary SSH software products.

  • OpenSSH - Distributes open source SSH software.

SSH Technical Specifications


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