XWin works on Win2K but not on some WinXP clients [FIXED]

[Harold L Hunt II]

Kirk,

Well then, I suppose the next step would be to do a "telinit 3" (to stop 
gdm), then edit xinetd conf file to run "echo" on UDP port 177, restart 
xinetd, then use that udp echo client that we found to test if echo 
works from the Windows XP machine plugged into its normal jack to gaia 
plugged into its normal jack.  We know that echo worked on UDP port 7, 
but proving that it does or does not work on UDP port 177 would tell us 
if they know what they are talking about :)

Harold

Woellert, Kirk D. wrote:

> I aksed corporate IS if they were doing an port blocking/filtering within
> our LAN. They replied:
> 
> "There should be no port blocking within the corp. LAN. - only in/out to the
> Internet and in/out of DMZs."
> 
> 
> 
> -----Original Message-----
> From: Harold L Hunt II [mailto:huntharo@msu.edu]
> Sent: Monday, November 17, 2003 10:45 AM
> To: cygwin-xfree@cygwin.com
> Subject: Re: XWin works on Win2K but not on some WinXP clients [FIXED]
> 
> 
> Kirk Woellert's problem with XP clients has been fixed, sort of.
> 
> I talked to him on the phone for a few hours on Friday and walked him 
> through some debugging.
> 
> 
> Here is what we found out:
> 
> 1) We could ssh from XP to Linux (TCP protocol).
> 
> 2) We could tunnel X apps over ssh from the Linux box to display on the 
> XP box (TCP protocol).
> 
> 3) We could natively display X apps by exporting DISPLAY on Linux box, 
> pointed to XP box (TCP protocol).
> 
> 4) We could not (nor could X-Win32) get an XDMCP login on the XP box for 
> the Linux box (UDP protocol).
> 
> 5) We could run the echo service on the Linux box on port 7 and use a 
> Java echo client for UDP to verify that UDP to Linux box worked (UDP 
> protocol).
> 
> 6) It was revealed that there are really two parts of the network here. 
>   Not much is known about whether port blocking is in effect between the 
> two parts.
> 
> 7) Removing the troubled hosts from the network and hooking them to a 
> stand-alone hub with assigned IP addresses allowed XDMCP to work.
> 
> 8) We thus confirmed in #5 that UDP was not blocked in general, but #7 
> indicates that UDP port 177 is blocked between the segments.  It turns 
> out that all of the Windows 2000 machines were on one "segment", while 
> the Windows XP machines were on another "segment".  The problem was not 
> the OS, it was that one segment has UDP port 177 blocked.
> 
> 
> Thus, we determined that the problem is in the network that the machines 
> are attached to; this may or may not be by design.  In any case, it 
> isn't a problem with Cygwin/X.  :)
> 
> Harold