Re: how to login from old pc to new pc

[jereme <jereme@rmcnet.cc>]

Hi Roman,

Roman Brodylo <roman.brodylo@mnet-online.de> writes:
> I want to use my old PC as a second "Terminal" on my new system, but
> how the .... do you do that?

It sounds like you want to be able to log in to an X environment
displayed on old_box but with new_box hosting the session, (doing all
the work).  Is that correct?

If so, here are some thoughts, (this is a *big* topic, as you no doubt
discovered from the mountain of docs you found) fear not, it all fits
together nicely in the end.  This is not a silver bullet but it will
help you to get started and give you someplace to work from, (you
sound like the self starting type ;)

First, if you haven't already, get ssh working on new_box so you can
log in from old_box.

Then start learning about the wonders, (and inherent inescurites) of
X.  The real power, (and elegence) of X is the idea of network
transparency.  An X application doesn't care where it is running or
where it displays it's output, (and gets it's input).  They can and
often are seprate hosts.

First, on old_box, check that the running X server is listeing for
connections from remote clients.  For the first display on your host,
you should find that 6000/tcp is open, check with 'netstat --inet
-an'.  If it isn't, it just means your X server was started with the
'-nolisten tcp' switch, (a good idea for most folks who don't intend
to do what we want).  

If you have a display manager, (do you log in to X at a grphical
prompt or do you run the startx script from the CL?) it is starting
the X server for you and you just need to have it start it without
that switch.  For gdm, the config file is /etc/X11/gdm/gdm.conf, for
kdm, I believe it is under /etc/kde2 somewhere, xdm, has it's own as
well...  poke around.  The big picture is: find out how the display
manager is configured to start the local X server and make sure it
starts it without the '-nolisten tcp' switch.

Now, still on old_box, tell the running X server to allow clients to
connect from new_box.  Xauthority is a better system for controlling
access to the server but for now, start playing with xhost as it is
simpler.

$ xhost + new_box

This tells the X server on old_box to allow clients from new_box to
connect and make use of the display and input fascilities.

After logging in to new_box via ssh, export a DISPLAY variable:
$ export DISPLAY=old_box:0

This tells apps running as a child of the shell that exported that
variable where they can find a suitable display server.

Then fire up an X app, I like xeyes for testing as it is included in
the xbase-clients package which is generally installed already.  You
should find that the application is running on new_box, in your shell
but being displayed on old_box.  It is worth looking at netstat on the
two hosts to get a better sense of what is going on.

Once this all works, you will want to setup XDMCP so you can:

1. Avail yourself of the better security system, Xauthority, which is
   user centric as versus host centric and is session based, (and you
   get to use the cool term magic-cookie).

2. You will have a true Xterminal, a graphical display running on
   old_box that queries a session from new_box, the display manager
   process on new_box will display a login banner on old_box and your
   entire session will run off of new_box, (including the desktop
   environment, the largest load and generally the thing you most want
   to shift over to the newer, faster systems).


That was a allot of info and I glossed over a good deal but it should
give you something to start with, let us know how you fair, I can
always expound, good luck.




-jereme

-- 
+--------------------------------------------------------------+
Jereme Corrado <jereme@restorative-management.com>
System Administrator
Restorative Management Corp.

gpg: 1024D/9C39E1F0