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X11 Forwarding

X11 Forwarding

Mar 20, 2024

X11 forwarding is a special TCP/IP port forwarding case. The X11 protocol is used by a PC X server software, such as Xmanager, and the connection is established to a user PC from a remote host. It is thus the reverse situation from other client programs, such as email or telnet. Using X11 forwarding, remote X11 application programs can be used in a user's PC via a secure encoding tunnel without complicated port forwarding settings.                                                    To use the X11 forwarding service, you should configure both Xshell and the SSH server.

To Activate X11 Forwarding in Xshell:

  1. Open the Sessions dialog box.

  2. Select a session for which to activate X11 forwarding.

  3. Click the standard [Properties] button.

  4. Select [Connection > SSH > Tunneling] from [Category].

  5. Select [Forward X11 Connections to].

  6. If Xmanager® is installed in the user's PC, select [Xmanager]. If another PC X server is used, select [X DISPLAY] and enter an appropriate DISPLAY.

  7. Click [OK].

Note
In Xmanager, Xshell automatically finds the X DISPLAY option. In other PC X server programs, the option must be set manually. If PC X server uses TCP 6000 port, DISPLAY is set as 'localhost:0.0'.

To Activate X11 Forwarding in an OpenSSH Server:

  1. Open the /etc/ssh/sshd_config file.

  2. Set X11Forwarding option value as follows: X11Forwarding yes

  3. Restart SSH server.

To Activate X11 Forwarding in an ssh.com Server:

  1. Open the /etc/ssh2/sshd2_config file.

  2. Set AllowX11Forwarding option value as follows: AllowX11Forwarding yes

  3. Restart SSH server.