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

[Ken Coar]

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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