[lug] Using Xwindows with Linux 6

[Tkil]

>>>>> "RM" == "Robert S Mathias" <rmathias at lucent.com> writes:

RM> I just set up my linux6 box and want to configure Exceed to run an
RM> Xsession on the linux box. 

note that the x window system has very peculiar (and very particular)
terminology for things.  Exceed (so far as i know) is an x server
implementation that runs on top of ms windows.  i don't know of any x
clients that run on win32 and display on an x server.

your mention of "xsession" is another whole topic unto itself.
generally, an x server (either exceed or xf86) provides one or more
displays, each of which can have one or more screens.  (so when you
see something like DISPLAY=foo:0.3, that is x server "foo", display
"0", and screen "3").

xsessions are a way of letting users log into an x display directly,
which is necessary on e.g. x terminals, and some people prefer to have
their workstations boot into x directly, so you need to log in there
(contrast to logging in at a text terminal, then launching the x
server there).

common x session managers are xdm and (on linux) gdm, the gnu/gnome
display manager.

in this case, i believe that you want the following:

1. exceed as your x server on your windows box.  assuming that the
   machine name is "bill", exceed should provide at least the display
   "bill:0".

2. you want to manage xsessions on bill:0.  since i don't know whether
   exceed does this for you, i will assume that you want to run a
   session manager off of your linux box (let's call it "tux".)  so
   here, we have a session manager on tux as an x client, displaying
   on the x server bill.

given this, you need to configure the following:

1. tell the x server (on bill) to allow a session controller from tux
   to display on the screen.  i don't know precisely how to do this,
   since this is a change you will have to make to your exceed
   configuration.

2. set up user accounts on tux.

3. tell tux to run a session manager (either xdm or gdm) on bill.  you
   might have to specify a set of users which can log in through this
   session manager.

that should be all you need; the permissions (to allow x clients
running on tux to display on bill:0) should be handled by the display
manager.  (if not, "man xauth" on the linux box for a good starter.)

there should be examples in the exceed documentation that explain how
to connect to a session manager running on another host.  once you
have that working, you only need to get the display manager of choice
running on tux, tell exceed to ask tux for session management, and the
rest should "just work".

RM> when I complete the setup, I get a error that states " unable to
RM> connect to server using start method specified" . I have asked my
RM> Unix guru buddies and they state that on a Unix box, there is a
RM> "netgroup" file that enables certain remote machines "Xwindows "
RM> access. What is the equivalent linux file that I need to modify in
RM> order for a successful Xwindows session? Is there also a specific
RM> command line that must be specified in Exceed? If so, what is it?

the exceed docs should cover most of this.  if you would like to test
the exceed system without setting up the full rigamarole above, you
need to do at least this:

1. start exceed on "bill".

2. tell it to allow all connections from "tux".  on unix boxes, this
   is most often done with "xhost +tux"; i'm not sure how you tell
   exceed to allow connections from a given host (or from all hosts,
   but that is *very* insecure; allowing all connections from just one
   machine should be just as secure as that one machine is.  xauth
   (for per-connection/per-user security) is better yet.)

3. using the win32 telnet client (or a better one, if you have one on
   bill), telnet to tux and log in.  after you log in, you need to
   tell your unix environment where to send x clients:

      $ export DISPLAY=bill:0

   for sh/ksh/bash, and for csh:

      % setenv DISPLAY bill:0

4. test the connection to see if it works.  try launching a simple
   xterm on the linux box:

      xterm &

   it should display on bill:0.

there should be lots of good documentation about this type of thing.
if you can't find any yourself, let us know, and we'll try to find
some for you.

t.