RE: SSH Notes

["Harold Hunt" <huntharo at msu dot edu>]

> -----Original Message-----
> From: cygwin-xfree-owner@cygwin.com
> [mailto:cygwin-xfree-owner@cygwin.com]On Behalf Of Alexander Gottwald
> Sent: Friday, October 04, 2002 5:57 AM
> To: cygwin-xfree@cygwin.com
> Subject: Re: SSH Notes
>
>
> Harold L Hunt II wrote:
>
> > ssh should assume ``DISPLAY=127.0.0.1:0.0'' when the DISPLAY
> variable is
> > not set on the Cygwin host.  I am not sure why this is not
> currently the
> > case.  I can only guess that the lack of this assumption is
> either do to
> > 1) a whiny security geek on the openssh project, or 2) that the assumed
> > usage scenario for openssh is more like a Linux/X machine where
> you have
> > probably got your X Server running when you connect to your remote
> > machine with ssh, thus DISPLAY would already be set.
>
> What if you are remote on an machine (linux or cygwin, does not
> matter) and
> a user has already started a xserver on localhost:0.0. You are not allowed
> to connect. So you don't set DISPLAY. If ssh would automaticly set DISPLAY
> it would try to connect to an xserver which then refuses the connect.
> ssh would abort because of an error. Not setting DISPLAY means
> "don't use X"
>

That doesn't make any sense.  ssh picks up the DISPLAY value on your Cygwin
host because it needs to know where to direct the data that comes in over
the X11 tunnel.  So, a DISPLAY of 127.0.0.1 on your Cygwin host can only
cause ssh to try to connect to the X Server on your Cygwin host ---
127.0.0.1 does not mean that ssh will try to connect to the remote host's
local X Server.

My point is, why on earth did the user run ``ssh -X [...]'' if they did not
want to actually enable X11 tunnelling?  I would say it is a pretty safe
assumption that they want to use the X Server on their Cygwin host to
display the tunnelled data.  Most users are entirely confused when they run
``ssh -X [...]'' and X11 tunnelling does not actually get enabled.  We
should not be making users jump through any hoops to use X11 tunnelling.

> If users want DIPLAY explicitly set they can add it to their .profile
>

Are we talking about the same type of users?  :)

Harold

> bye
>     ago
> --
>  Alexander.Gottwald@informatik.tu-chemnitz.de
>  http://www.gotti.org           ICQ: 126018723
>