KB-0366: How to configure Centrify OpenSSH for X11 forwarding

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KB-0366: How to configure Centrify OpenSSH for X11 forwarding

Product:

Centrify DirectControl ,

Published:

12 April,16 at 11:06 AM

Rating:

Question:

How to configure Centrify OpenSSH for X11 forwarding?

Answer:

Server Side:
In order to configure ssh to do X11 forwarding, the following settings need to be applied in the sshd config files:

In /etc/centrifydc/ssh/sshd_config
Search for the following line:
- #X11Forwarding no
Change this to:
- X11Forwarding yes

Client Side:
Linux:
Add the following lines into be added in the ssh_config file on the client side:

ForwardX11 yes
ForwardX11Trusted yes

Save the configurations, then restart sshd.

After a restart, the $DISPLAY environment variable will be set and the needed .XAuthority files will be created.

Additional steps for Fedora Core / RHEL / CentOS:

Either create a link to /usr/bin/xauth by running:

cd /usr/X11R6/bin
ls
ln -s /usr/bin/xauth xauth

Or add the following configuration:

XAuthLocation /usr/bin/xauth

Additional steps for Solaris:

Edit /etc/centrifydc/ssh/sshd_config and configure the line to listen on:
- 0.0.0.0
In the startup script, change the startup line for 'ssh' to start with 'sshd -4'
Stop and restart the Centrify sshd service.
ssh -X should now work.

Windows:
Download and install Xming X server for Windows:

https://sourceforge.net/projects/xming/

PuTTY Client:

Check the following box on Putty client: Connection -> SSH -> X11 -> "Enable X11 forwarding"

Additional Notes:

There is a known issue with stock Solaris SSH, Bug 6704823 Fix for 6684003 prevents ssh from X forwarding on IPv4-only system, was filed with Solaris/ssh:
- http://bugs.opensolaris.org/view_bug.do?bug_id=6704823

Workaround for stock SSH (not Centrify)

Add the lo0 interface for IPv6, for example:
- ifconfig lo0 inet6 plumb up
To make this change permanent, run:
- touch /etc/hostname6.lo0
Disable IPv6 ssh support and change ListenAddress to 0.0.0.0 in /etc/ssh/sshd_config, then restart sshd with the "-4" option. For example:
- svcadm -v disable ssh
- /usr/lib/ssh/sshd -4

Centrify Corporation does not take any responsibility for the content or availability of the links in this article and it was provided as a courtesy. Customers should contact the vendor if there are any further questions.