Re: "Cannot open display" or XDMCP problem ?

[Enoch Wu <ewu at eskimo dot com>]

Hey my friend. Check your environment variable OS. Is it empty?
If not, export OS="" in .bashrc.  After that restart cygwin and
run startxwin.bat from bash.

Hope it helps
EW

On Tue, Apr 10, 2001 at 03:20:10PM -0500, Robert, Francois wrote:
> Dear all
> I am experiencing a problem which sounds very similar to one mentionned in
> various threads "cannot open display". I therefore apologize if this is the
> Nth version of the same problem, but I must also admit that even after
> reading those postings, I was unable to reconstruct the exact scenario that
> those threads referred to.
>  
> -----------
> My situation is as follow :
> 
> Win95 (OSR2) + Cygwin 1.1.8 + XFree 4.0.3 (binaries) 
> 
> My IP address is obtained from DHCP server
> 
> my Windows' c:\windows\hosts :
> 127.0.0.1       localhost
> 
> I have a comment-only Cygwin's /etc/hosts file 
> 
> I have a /etc/X0.hosts as follow :
> 129.227.62.246
> 129.227.62.61   <--- my IP at that moment I tried (just to be sure)
> 
> I have an export DISPLAY=127.0.0.1:0.0 in my .bashrc (and env shows me the
> DISPLAY variable this way too)
> -------------
> 
> I am trying to connect to a Solaris machine. I thus tried to connect using
> the -query option and I expect to get the CDE login screen.
> 
> XWin95 -screen 0 1024x768x16 -whitepixel 255 -blackpixel 0 \
> -query 129.227.62.246 & 
> xhost +  &
> 
> But all I get is an empty X background screen that vanishes after about one
> minute and leaves me the following diagnostics : 
> 
> $ winCreateB... () - Adjusted width: 1018 height: 715
> winCreateB... () - width: 1018 height: -715
> winCreateB... () - dibsection width: 1018 height: -715
> error opening security policy file /usr/X11R6/lib/X11/xserver/SecurityPolicy
> AUDIT: Tue Apr 10 21:26:41 2001: 184093 XWin95: client 1
> rejected from IP 127.0.0.1 port 4295
> Xlib: connection to "127.0.0.1:0.0" refused by server
> Xlib: Client is not authorized to connect to Server
> xhost:  unable to open display "127.0.0.1:0.0"
> 
> francoisr@FR-ROBERTF-W95 /home/francoisr
> $Fatal server error:
> XDMCP fatal error: Session failed Session 139 failed for
> display 0.0.0.0:0: Cannot open display
> ----------------
> 
> Now, xhost + works perfectly (and so does the following :
>   xterm -sl 1000 -sb -rightbar -ms red -fg yellow \
>     -bg black -e bash &
>   twm &
> )
> if I work "standalone", without the -query option.
> 
> The other postings did not mention DHCP nor the -query option, so I am not
> sure whether this is actually the same problem, or if I have a configuration
> problem, or whatever. Also, my understanding is that my (inexistant)
> SecurityPolicy file for which I receive an error message is not the culprit
> here.
> 
> -----------
> Just in case, and as suggested in other postings, I peeked at network
> activity with netstat :
> 
> XWin95 -screen 0 1024x768x16 -whitepixel 255 -blackpixel 0 \
> -query 129.227.62.246 & 
> netstat -a -n > netstat.log &
> xhost +  &
> 
> The following ended up in netstat.log : 
> Active Connections
> 
>   Proto  Local Address          Foreign Address        State
>   TCP    127.0.0.1:4665         127.0.0.1:4664         TIME_WAIT
>   TCP    127.0.0.1:4667         127.0.0.1:4666         TIME_WAIT
>   TCP    127.0.0.1:4669         127.0.0.1:4668         TIME_WAIT
>   TCP    127.0.0.1:4671         127.0.0.1:4670         TIME_WAIT
>   TCP    127.0.0.1:4673         127.0.0.1:4672         TIME_WAIT
>   TCP    129.227.62.61:1590     129.227.136.25:1058    ESTABLISHED
>   TCP    129.227.62.61:1598     129.227.136.25:1073    ESTABLISHED
>   TCP    129.227.62.61:1606     129.227.136.25:1058    ESTABLISHED
>   TCP    129.227.62.61:1620     129.227.136.25:1073    ESTABLISHED
>   UDP    0.0.0.0:1591           *:*                    
>   UDP    0.0.0.0:1592           *:*                    
>   UDP    0.0.0.0:1607           *:*                    
>   UDP    0.0.0.0:1608           *:*                    
>   UDP    129.227.62.61:137      *:*                    
>   UDP    129.227.62.61:138      *:*                    
> -------------
>  
> I would appreciate any advice on how to get the XDMCP connection working.
> 
> Regards
> François
>