Can't make X tunnelling via SSH work, probably loosing my mind....

[George Hartzell]

I just noticed that I couldn't ssh -X from a machine into a fully
configured jail on the same machine and have an X app display back on
the desktop.

I think that this used to work, but I can't swear to it.

I've been playing around, and now have pretty much everything on the
machine stripped down.  No jails, no ipfw, no interface aliases.

It's running 5.4-STABLE as of a few days ago, and everything is
compiled from ports and should be up to date.  The video cards a
matrox 550 and I'm running with mga_drv.o and mga_hal_drv.o from the
mgadriver-4.1 tarball from the matrox site.  It's dual headed w/ a
pair of NEC Multisync LCD1850X's on a dual-headed DVI cable.

It turns out that I can't ssh -X from that machine into any other
machine and have it work.  I can, however, ssh -X from another machine
(e.g. 5.3BETA4 laptop) into it and display onto the laptop.

In particular, it can't even ssh -X into itself and display an X app.

There's some information at

  http://grapeape.alerce.com/screwball

including netstat and /etc/rc.conf and an ssh -v -v -X session.

If I ssh -X into itself and run xeyes, it just sits there.  If I do a
tcpdump -i lo0 from another window, there's a flood of traffic back
and forth between the .ssh port and a variety of ports including
.x11-ssh, one at 6011 [I think that the DISPLAY as localhost:11 that
time around], and a bunch of other randomish.

I've tried it with X11UseLocalhost on and off.

At this point my eyes are crossed and I can't even figure out what to
try next.  And, I'm not feeling particularl bright, I'm sure it's
going to turn out to be something obvious....

Anyone have any thoughts?

g.