Client Pgms

Here are a few commonly asked client setup questions. The focus of these setups will be to use secure communications to the i5/OS from your Windows or Linux machine. There are multiple “pay for” X clients for Windows that have great performance, but the offerings featured below are considered “no charge”, and can be “easily” used as i5/OS secure sshd clients.


  • LinuxSSH Best - use ssh -X (or ssh -Y) for secure access to i5/OS (fast GUI without VNC running on i5/OS)


  • Xming - free X Server to use with putty ssh
  • XWinLogon - free cygwin subset X windows to compete with XWin32 and eXceed.
    • Compare - XWinLogon, XWin32 and eXceed.
  • Cygwin - X for windows
    • CygwinSSH ssh -X (or ssh -Y) for secure access to i5/OS (fast GUI without VNC running on i5/OS)
  • PuttySetup putty - PuTTY is a free terminal emulation program for Windows.
    • PuttySSHCygwin Faster - Use putty for secure Cygwin to i5/OS (GUI)
    • PuttySSHVNC Slower - Use putty for secure VNC to i5/OS (GUI)
    • PuttySSHMySQL - Use putty for secure MySQL administration (Client/Server GUI)
    • PuttySSHi5OS - Use putty for secure ssh to i5/OS (PASE command — no GUI)


You will need to edit the sshd_config file to enable X11Forwarding yes.

  • V6R1 /QOpenSys/QIBM/UserData/SC1/OpenSSH/openssh-3.8.1p1/etc/sshd_config
    • X11Forwarding yes
  • prior /QOpenSys/QIBM/UserData/SC1/OpenSSH/openssh-3.5p1/etc/sshd_config
    • X11Forwarding yes

IBM i version vary over time/PTFs, so follow the links /QOpenSys/QIBM/UserData/SC1/OpenSSH

Depending on your client version of ssh, the “ssh -X” option may no longer works as it did in the past. It may use the XSECURITY extension by default, and 99.9% of all applications are written without any clue about XSECURITY. The usual sign of this is a bunch of “BadAtom” errors or other unexpected errors. If you want to get X11 forwarding you may have to use client “ssh -Y” option instead of “ssh -X”.


Tony “Ranger” Cairns - IBM i PHP / PASE