RE: XDMCP - Solaris 8.4 - CygWin

[Alexander Gottwald <alexander dot gottwald at informatik dot tu-chemnitz dot de>]

On Tue, 3 Jul 2001, Harold Hunt wrote:

> Stefan,
> 
> > This works:
> > $[W2K] XWin -screen 0 800x600 &
> > $[W2K] xhost + &
> >
> > $[U60] export DISPLAY=W2K:0
> > $[U60] xterm &
> 
> Right, that should work, as it has nothing to do with XDMCP.  You knew that
> though, right?
> 
> > This won't work:
> > $ XWin -screen 0 800x600x32 -from W2K -query U60 &
> > $ xhost + &
> >
> > The error I get on W2K is:
> > Fatal server error:
> > XDMCP fatal error: Manager unwilling Host unwilling

This seems to be a xdm configuration problem. Please check the Xaccess file
(/usr/X11R6/lib/X11/xdm/Xaccess or /etc/X11/xdm/Xaccess) .
There must be the following entries.
--8<---8<--
windows.host.name CHOOSER BROADCAST
windows.host.name
--8<---8<--
You can use wildcards in the hostnames too (eg. *.local.domain) but 
please check the comments inside Xaccess and the xdm manpage if you want to
use them.


> > XIO:  fatal IO error 104 (Connection reset by peer) on X server
> > "127.0.0.1:0.0"
> >       after 0 requests (0 known processed) with 0 events remaining.
> 
> Well, I don't know a lot about XDMCP, but I can tell you that I use it to
> connect to my Linux boxes all the time.  Try connecting to another machine
> that you know to have a working XDMCP server (such as a Red Hat or Mandrake
> machine, which generally come with XDMCP enabled by default).
> 
> I remember that people have had problems when trying to run local clients
> together with an XDMCP session to a remote host.  Try removing all clients
> from your startup scripts, so that the only thing you are running is
> XWin -screen 0 800x600 -query U60.  (I haven't had to use the -from
> parameter for some time now, you may be a able to drop it as well).

The problem with the local clients is because of the security managment
in the xserver. The clients have to authenticate to the xserver. This can
be done using 
a) the hostname
b) an token, generated by xdm

xhost + or xhost hostname will enabale all connections from all, or the 
named hosts. 
But normally any client will first try the tokens from ~/.Xauthority
which can be listed with "xauth list". If you have connected via xdmcp, the
server knows a token, which was generated by the remote xdm. This token is
only known to the server and the session (windowmanager, shell and all forked
clients) on the remote machine. But the token is not known to the clients on
the local machine (where the xserver runs). If you want to connect from the 
local host to the local xserver, you must copy the token. 
if you use ssh, this might help (not tested)
xauth add $(ssh remotehost xauth list localhost:0)
This should copy the token to the local computer.



> In any case, if the above doesn't help, I think you will need to look for
> some general XDMCP documentation or a mailing list for that topic, as this
> list isn't specific to XDMCP.  However, do report your results to this list,
> as we will then be able to update the User's Guide and FAQ to help other
> users that encounter your problem in the future.

normally man xdm helps. The config files for xdm are very well documented.

HTH
	ago
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 Alexander.Gottwald@informatik.tu-chemnitz.de 
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