LinuxSA Mailing list archives

  From: Sulis, Adam <SULISA@tc.gc.ca>
  To  : Sulis, Adam" <SULISA@tc.gc.ca>, Linux SA <linuxsa@linuxsa.org.au>, "'Martin Sandiford' <SULISA@tc.gc.ca>
  Date: Fri, 17 Sep 1999 09:54:00 -0400

RE: Confiuring XDMCP Broadcast

Thanks for the smack in the head. I needed someone to get me back on track.
I am picking up on a few concepts as I go along. The "X" exists on the linux
box and works OK. I changed /etc/inittab to not load prefdm, but rather to
load xdm instead. After a reboot, The xlogon widget comes up (although much
uglier than the gnome). After logging in, I get an Xterm on the desktop.

Although I am confident I'll find the solution to the following mysteries, I
won't turn away any futher advice. Thanks again. Here are my new horrors:

- Instead of Xterm, I would like the complete desktop as shown on the server
in default configuration (for Redhat6, that's GNOME, I think). So I have to
change that. Possibly by adding "-session session_program" to the end of xdm
in /etc/inittab. I may have to script it if it can't be done in one command.

- Paths are a problem in the new display. Even though Xterm is in
/usr/X11R6/bin, I still have to launch by typing /usr/X11R6/bin/xclock, for
example. This may be adjustable by a script, or Xsession, or something. I'll
keep experimenting.
> Adam 
> ----------
> From: 	Martin Sandiford[SMTP:ms@mcdev.com.au]
> Sent: 	Thursday, September 16, 1999 10:30 PM
> To: 	Sulis, Adam; Linux SA
> Subject: 	Re: Confiuring XDMCP Broadcast
> 
>     Adam> Hi group: I have installed XWin32 for Windows 95, and am
>     Adam> trying to connect to a Redhat 6 box. I would like to be able
>     Adam> to:
> 
>     Adam> 1. Have the box show up on the XDMCP Selector list
>     Adam> 2. Run a full desktop session on XWin32 (RSH, single window)
> 
> These seem to be different things.  If you are using XDMCP, you do not
> need to use rsh to login.
> 
> You will need to start xdm (or on redhat 6, /etc/X11/prefdm).
> 
> You can then use the XDMCP option with X-Win32 to connect to the Linux
> box.
> 
> There are normally three ways that you can connect to an xdm server
> using an X server:
> 
> 1. Specify the IP address of the xdm server you wish to connect to (aka
> "query" mode).  If all is well, a login window will be displayed on the
> X server, and you will be logged into the xdm server.  You need to
> specify the IP of the xdm server to log in to.
> 
> 2. Use broadcast mode, where the X server sends out broadcast requests
> to connect to an xdm server.  The first xdm server that responds is the
> one you get a login window for. You do not need to specify IP addresses.
> 
> 3. Use "indirect" mode, where the X server requests that xdm server to
> run a "chooser" which displays a list of hosts that you can log in to
> with xdm.  You then choose one, and are logged in.  You will need to
> specify the IP address of the xdm server which will display the chooser.
> 
> If you are using RH6 and gnome, then you are probably using gdm.  I have 
> not been able to get gdm to display a chooser for indirect mode, but I
> have been able to get xdm to work fine.  If you wish to try with xdm,
> you can "cd /etc/X11" and then "ln -sf /usr/X11R6/bin/xdm prefdm".
> 
> I believe that XWin32 supports all of these options under the session
> setup (?).
> 
>     Adam> Here are my observations so far (thanks to the archive for
>     Adam> reference):
> 
>     Adam> 1. I can get applications up by manually initiating a remote
>     Adam> login: - Double-Click XWin32 - telnet to the Redhat box (in
>     Adam> my case 1.2.3.1) - log in as root - issue "export
>     Adam> DISPLAY=1.2.3.2:0.0" where 1.2.3.2 is the 95 box - issue
>     Adam> "xcalc" (or xterm, netscape, or other x app)
> 
> Good - pretty much all the components are working.
> 
>     Adam> 2. I modified the /etc/X11/xdm/Xservers file as follows:
>     Adam> changed: :0 local /usr/X11R6/bin/X to: :0 local
>     Adam> /usr/X11R6/bin/X -broadcast and restarted the box hoping
>     Adam> that would cause the broadcast.
> 
> This is probably not what you want.  Xdm will start local server(s) and
> show login windows on them if you wish.  If you do not need a local
> server, then comment this line out. In any case, you do not need the
> -broadcast.  -broadcast asks the local X server to connect to an xdm
> server, which happens automagically for servers started by xdm anyway.
> 
> If you do not want to have X started automatically on the linux box, you 
> can comment this line out altogether.
> 
>     Adam> The Redhat box is configured with defaults, and works with
>     Adam> manual login, so I suspect that I have to alter the server
>     Adam> parms to allow XDMCP broadcasts.
> 
> Yes, but probably on the X server, not the xdm server.  Have a look in
> the XWin32 setup options for XDMCP stuff. This is what you want.  Also
> read above about gdm vs xdm.
> 
> A word of caution: the /etc/X11/xdm/Xaccess file specifies who will be
> able to get a login window and/or a chooser from your xdm server.  As
> shipped, RH6 allows *anyone* to get a login and/or chooser.  Some people
> may consider this a security flaw.
> 
>     Adam> I am having trouble finding documentation to RTFM. Perhaps
>     Adam> if someone could point me in the right direction. This would
>     Adam> make an excellent HOWTO.
> 
> /usr/doc/HOWTO/mini/Remote-X-Apps is a good place to start.
> 
>     Adam> Any hints would be appreciated by this newbie.
> 
> Cheers,
> Martin
> 
> -- 
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