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RE: 6.7.0.0-4: Unable to connect to remote server using DMCP
- From: Bailey Wier <bwier at marketaxess dot com>
- To: "'cygwin-xfree at cygwin dot com'" <cygwin-xfree at cygwin dot com>
- Date: Thu, 15 Apr 2004 17:13:22 -0400
- Subject: RE: 6.7.0.0-4: Unable to connect to remote server using DMCP
- Reply-to: cygwin-xfree at cygwin dot com
Thanks, Daniel...
I figured this one out using your tcpdump suggestion. For reference, it
appears that the network routing or dns tables had an older cached reference
for the IP address I was making xdmcp requests from. Thus, xdm resolved an
invalid hostname for the source address and sent packets to a non-existing
host.
e.g.:
C:\cygwin>hostname
NYC-5XB1R31.marketaxess.com
C:\cygwin>XWin.exe -query nyc-hhgas.marketaxess.com
nyc-hhgas:/var/log # tcpdump -i eth0 -l udp port xdmcp
tcpdump: listening on eth0
17:08:51.760754 nyc-wr0vs.marketaxess.com.mice >
nyc-hhgas.marketaxess.com.xdmcp: udp 7
17:08:51.790810 nyc-hhgas.marketaxess.com.xdmcp >
nyc-wr0vs.marketaxess.com.mice: udp 52 (DF)
17:08:52.451785 nyc-wr0vs.marketaxess.com.mice >
nyc-hhgas.marketaxess.com.xdmcp: udp 66
17:08:52.453015 nyc-hhgas.marketaxess.com.xdmcp >
nyc-wr0vs.marketaxess.com.mice: udp 52 (DF)
17:08:52.453457 nyc-wr0vs.marketaxess.com.mice >
nyc-hhgas.marketaxess.com.xdmcp: udp 29
17:08:54.458327 nyc-wr0vs.marketaxess.com.mice >
nyc-hhgas.marketaxess.com.xdmcp: udp 29
17:08:57.113586 nyc-gwb1r31.marketaxess.com.xdmcp > 255.255.255.255.xdmcp:
udp 34
17:08:58.458581 nyc-wr0vs.marketaxess.com.mice >
nyc-hhgas.marketaxess.com.xdmcp: udp 29
> On Thu, 15 Apr 2004, Bailey Wier wrote:
>
> > I have upgraded to the X/Cygwin 6.7.0.0-4 but find that I am unable to
view
> > the login screen on a SuSE Linux box. Basically, the XWin window
appears
> > but does not show any of the KDM GUI or login on the remote server. The
> > screen is simply a gray background with the 'X' cursor.
>
> The grey background with the X is the X server in the "default" state. You
can
> end up with this for any number of reasons.
>
> Since you're trying to get XDMCP to work here, run xdm/kdm on the SuSE box
in
> debug mode and check the logs. Are you getting any connections from your
> Windows box at all?
>
> Also try to tcpdump at the SuSE box, "tcpdump -i eth0 -l udp port xdmcp"
or
> something.
>
> --
> Daniel Mikkelsen
> Copyleft Software AS