[libvirt-users] virt-viewer X forwarding through ssh broken since FC17 upgrade?

Dave Allan dallan at redhat.com
Tue Nov 13 17:10:34 UTC 2012

Hi Ken,

Does adding a listen='localhost' to the guest's graphics tag fix it?


On Tue, Nov 13, 2012 at 11:59:25AM -0500, Ken Coar wrote:
> Ever since I upgraded my laptop from FC15 to FC17, I've been
> getting this message when I ssh to some RHEL6 hosts inside Red Hat.
> In particular, I'm trying to do this:
> virt-viewer --connect \
>     qemu+ssh://kvm11.devlab.phx1.redhat.com/system \
>     bork-s01.candlepin.dev.devlab.phx1.redhat.com
> This is the message I get:
>   X11 forwarding request failed on channel 0
> A viewer window pops up for a fraction of a second and then
> goes away.
> Using -vvvv on the local ssh command gives a few possibly
> related messages:
> debug2: x11_get_proto: /usr/bin/xauth  list :0.0 2>/dev/null
> debug1: Requesting X11 forwarding with authentication spoofing.
> debug2: channel 0: request x11-req confirm 1
> debug1: Requesting authentication agent forwarding.
> debug2: channel 0: request auth-agent-req at openssh.com confirm 0
> 	:
> debug1: Remote: No xauth program; cannot forward with spoofing.
> This is new, and, not being an X maven, largely opaque to me.
> xauth is provided by package xorg-x11-xauth, which is typically
> *not* installed.  Installing it on the system to which I'm
> trying to ssh gets rid of the message, but doesn't change the
> up-down behaviour of the viewer window.
> Temporarily moving my local /usr/bin/xauth leads to this
> message in addition:
>   Warning: No xauth data; using fake authentication data for X11 forwarding.
>   X11 forwarding request failed on channel 0
> Since there's a window popping up at all, I doubt this is directly
> related to the problem getting the viewer to run.  However, on
> systems *with* xauth installed 'echo $DISPLAY' shows a value, but
> on those *without* xauth, $DISPLAY is null.  (So why am I getting
> any sort of X popup at all in that case?)
> Has anyone else seen this, and hopefully have a solution?  The
> problem is actually two-fold:
> 1. Why 'X11 forwarding failed' and how to get rid of it/revert to
>    behaviour in previous versions; and
> 2. Why is virt-viewer dying and how to keep it alive.  (Again, how
>    to revert to 'it *used* to work' conditions. ;-) )
> Thanks!
> -- 
> #ken	B-)}
> Ken Coar, RHCE, RHCSA, Sanagendamgagwedweinini
> IT Engineering Tower, Red Hat/RDU
> "Millennium hand and shrimp!"

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