RE: XDMCP?

[David Forrest <drf5n mug sys virginia edu>]

I'm not using gdm right now, but I think the difference is that it does
support xdmcp, but does not provide an indirect chooser service --- you
should be able to run a chooser program on your sum machine which looks
around for xdmcp managers.  The indirect chooser service is for fairly 
dumb x terminals that rely on a third machine to collect a list of
possible xdmcp managers.  I think the below means that gdm can control an 
x terminal, but cannot provide the chooser service directly. 

I havent seen much documentation, but what you may need to do on the sun
machine is run a program called 'chooser'  that might look for xdmcp
managers.  If the sun machine doesn't provide a choice list, it is
managing the display istelf, and won't listen for your linux box's xdmcp.


On Tue, 2 May 2000, Paul Gillooly wrote:

> Hello,
> 
> I have included the two messages below referring to XDMCP since
> they confuse me, in one it seems you are saying that it is
> possible to do XDMCP (using the chooser, how else is it useful?)
> in the other you say it is impossible. Now please forgive me if
> this is really silly but can I setup GDM so that I can startup
> Linux on my machine and use it to login (and start an X session)
> on a Sun machine downstairs?
> 
> Thanks, Paul.
> 
> 
> > -----Original Message-----
> > From: Martin K. Petersen [mailto:mkp sunsite auc dk]
> > Sent: Sunday, April 16, 2000 2:49 PM
> > To: dforrest virginia edu
> > Cc: gdm sunsite auc dk
> > Subject: Re: a FAQ? How dos one make gdm do XDMCP?
> > 
> > 
> > 
> > >> GDM is a standalone daemon which uses the tcp wrappers library for
> > >> access control.
> > 
> > David> So this means that it is its own daemon, and it uses the
> > David> entries in hosts.allow and hosts.deny, but not inetd.conf?  
> > 
> > Yep. GDM uses the tcp wrappers *library*, not the tcpd daemon.
> > 
> > 
> > David> So the output from '/usr/sbin/tcpd -a -v' which warns as shows
> > David> below is acceptable?
> > 
> > Looks alright, yes.
> > 
> > -- 
> > Martin K. Petersen	Principal Linux Consultant, Linuxcare, Inc.
> > http://mkp.net/		XFS, Linux/PA-RISC, GNOME, SunSITE Denmark
> > 
> > 
> 
> > -----Original Message-----
> > From: Martin K. Petersen [mailto:mkp mkp net]
> > Sent: Wednesday, April 19, 2000 11:04 AM
> > To: Soeren Thing Andersen
> > Cc: gdm sunsite auc dk
> > Subject: Re: More XDMCP problems.
> > 
> > 
> > >>>>> "Soeren" == Soeren Thing Andersen <thing control auc dk> writes:
> > 
> > Hi there,
> > 
> > Soeren> I run gdm (ver. 2.0beta2) on thing.stud.ies.auc.dk (RH6.2).
> > Soeren> When I try to connect from hvil.stud.ies.auc.dk with X
> > Soeren> -indirect thing I get a loginscreen instead of the hostchooser
> > Soeren> I expected.
> > 
> > GDM doesn't implement choosing yet.  I have it running in a devel
> > tree, but:
> > 
> >         Choosing is a horrid kludge which isn't part of the XDMCP
> >         spec.
> > 
> >         Choosing breaks a lot of other stuff.  I had to redesign most
> >         of the daemon to get it running.
> > 
> >         Choosing is extremely vulnerable to DoS attacks.  I have a few
> >         ideas how to limit this, however.
> > 
> > So the answer is: Yes, I'll get it merged into the main tree
> > eventually, but you probably don't want to turn it on unless you
> > *really*, *really* need it.
> > 
> > -- 
> > Martin K. Petersen	Principal Linux Consultant, Linuxcare, Inc.
> > http://mkp.net/		XFS, Linux/PA-RISC, GNOME, SunSITE Denmark
> > 
> > 
> 
> 
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-- 
 Dave Forrest                                dforrest virginia edu
 (804)296-7283h 924-3954w      http://mug.sys.virginia.edu/~drf5n/