I have to use -X in conjunction with -Y, so ssh -XY remote_host

____________________________________________ Adam Wead Systems and Digital Collections Librarian Rock and Roll Hall of Fame and Museum 216.515.1960 (t) 215.515.1964 (f)

On Tue, Jun 4, 2013 at 1:33 PM, m.roth@5-cent.us wrote:

Les Mikesell wrote:

...

On rare occasions I want to run a remote X command (like 'meld' to interactively merge changes in files) and normally 'ssh -Y remote_host' from a terminal in an NX/freenx window that is acting as my desktop to start and any X program subsequently started would open in a new window via X-forwarding - at least when the target is a 5.x host. I don't do it often enough to remember if it ever worked when the remote side is 6.x, but today it is not setting the $DISPLAY variable, so I get: Error: Can't open display: Using -vv shows it at least trying to go through the motions:

debug2: x11_get_proto: /usr/bin/xauth list :1420.0 2>/dev/null debug1: Requesting X11 forwarding with authentication spoofing. debug2: channel 0: request x11-req confirm 0 debug2: client_session2_setup: id 0 debug2: channel 0: request pty-req confirm 1 debug1: Sending environment. debug1: Sending env LANG = en_US.UTF-8 debug2: channel 0: request env confirm 0 debug2: channel 0: request shell confirm 1 debug2: fd 3 setting TCP_NODELAY

But, $DISPLAY is not set to anything. What am I missing?

Does your sshd_config allow x forwarding?

  mark

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CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos

On Tue, Jun 4, 2013 at 1:55 PM, Les Mikesell lesmikesell@gmail.com wrote:

On Tue, Jun 4, 2013 at 12:44 PM, Adam Wead amsterdamos@gmail.com wrote:

...

I have to use -X in conjunction with -Y, so ssh -XY remote_host

No difference; ssh -Y user@centos_5_host 'echo $DISPLAY' returns localhost:11.0 ssh -XY user@centos_6_host 'echo $DISPLAY' returns nothing.

/etc/ssh/sshd_config is the default, with: X11Forwarding yes

I remember having a similar problem when the xauth program was missing on a box but this one has it installed.

I'm a little lost as to wny you're using -XY; I'd expect either a -X or a -Y option; not both.

from the man page: -X Enables X11 forwarding. This can also be specified on a per-host basis in a configuration file.

X11 forwarding should be enabled with caution. Users with the ability to bypass file permissions on the remote host (for the userâs X authorization database) can access the local X11 display through the forwarded connection. An attacker may then be able to perform activities such as keystroke monitoring.

For this reason, X11 forwarding is subjected to X11 SECURITY extension restrictions by default. Please refer to the ssh -Y option and the ForwardX11Trusted directive in ssh_config(5) for more information.

-x Disables X11 forwarding.

-Y Enables trusted X11 forwarding. Trusted X11 forwardings are not subjected to the X11 SECURITY extension controls.

although in trying it myself, I get:

[z@ds ~]$ ssh -X z@mote Last login: Tue Jun 4 11:35:17 2013 from deathstar [z@mote ~]$ echo $DISPLAY localhost:10.0 [z@mote ~]$ logout Connection to mote closed. [z@ds ~]$ ssh -Y z@mote Last login: Tue Jun 4 14:15:04 2013 from deathstar [z@mote ~]$ echo $DISPLAY localhost:10.0 [z@mote ~]$ logout Connection to mote closed. [z@ds ~]$ ssh -XY z@mote Last login: Tue Jun 4 14:15:19 2013 from deathstar [z@mote ~]$ echo $DISPLAY localhost:10.0 [z@mote ~]$ cat /etc/redhat-release CentOS release 6.4 (Final)

do you get error messages if you run xauth by hand?

[zep@mote ~]$ xauth Using authority file /home/zep/.Xauthority xauth> ? Commands: add exit extract help info list merge nextract nlist nmerge quit remove source ? generate xauth> list .... xauth> info Authority file: /home/zep/.Xauthority File new: no File locked: no Number of entries: 4 Changes honored: yes Changes made: no Current input: (stdin):3

-- Even the Magic 8 ball has an opinion on email clients: Outlook not so good.

On Tue, 4 Jun 2013, Les Mikesell wrote:

On Tue, Jun 4, 2013 at 12:44 PM, Adam Wead amsterdamos@gmail.com wrote:

...

I have to use -X in conjunction with -Y, so ssh -XY remote_host

No difference; ssh -Y user@centos_5_host 'echo $DISPLAY' returns localhost:11.0 ssh -XY user@centos_6_host 'echo $DISPLAY' returns nothing.

/etc/ssh/sshd_config is the default, with: X11Forwarding yes

I remember having a similar problem when the xauth program was missing on a box but this one has it installed.

Do you by chance have ipv6 disabled? If so try adding the following to /etc/ssh/sshd_config and restart sshd:

AddressFamily inet

Hope this helps.

Regards,