VNC works *only* when also connected to internet

jsundqui@buffnet.net jsundqui "at" buffnet.net
Fri, 24 Jul 1998 22:30:50 +0000


Suggestions welcome for figuring out this problem:

My Set up:

Linux laptop (redhat 4.x) running vncserver.
Win95 desktop running vncviewer.
Connection: the Win95 desktop "dials up" a ppp connection to the laptop
using the null modem driver over a null modem serial cable.

The problem:
The TCP/IP connection between the two machines is set up correctly, and
I can ping, telnet, etc. the laptop.  In fact, this message is written
right now offline on the laptop but through the desktop's X server (the
free MIX server, sorry I don't have the URL available).

When I try to use vncviewer *instead* of the X server, it works only if
I first connect the laptop through its modem to the internet via ppp.

Here are the logs of sessions:

First, the succesful log, with the laptop first connected up my ISP via
ppp.  Note, I have my laptop renamed to it's dynamically assigned
FQDN (as assigned by my ISP) through /etc/ppp/ip-up upon establishment
of the ppp connection (in order to avoid some sendmail problems I was
having):

24/07/98 12:44:52 Xvnc version 3.3.2
24/07/98 12:44:53 Copyright (C) 1997-8 Olivetti & Oracle Research Laboratory
24/07/98 12:44:53 See http://www.orl.co.uk/vnc for information about VNC
24/07/98 12:44:53 Desktop name 'X' (dppp48.buffnet.net:1)
24/07/98 12:44:53 Protocol version supported 3.3
24/07/98 12:44:53 Listening for VNC connections on TCP port 5901
24/07/98 12:44:53 Listening for HTTP connections on TCP port 5801
24/07/98 12:44:53   URL http://dppp48.buffnet.net:5801 

24/07/98 12:46:24 Got connection from client 10.0.0.1 
24/07/98 12:46:24 Protocol version 3.3 
24/07/98 12:46:28 Pixel format for client 10.0.0.1: 
24/07/98 12:46:28   8 bpp, depth 8 
24/07/98 12:46:28   true colour: max r 7 g 7 b 3, shift r 0 g 3 b 6
24/07/98 12:46:28 no translation needed 
24/07/98 12:46:28 Using hextile encoding for client 10.0.0.1 
24/07/98 12:46:28 rfbProcessClientNormalMessage: ignoring unknown
encoding type 3 
24/07/98 12:55:56 Pixel format for client 10.0.0.1: 
24/07/98 12:55:56   8 bpp, depth 8 
24/07/98 12:55:56   true colour: max r 7 g 7 b 3, shift r 0 g 3 b 6
24/07/98 12:55:56 no translation needed 
24/07/98 12:55:56 Using hextile encoding for client 10.0.0.1 
24/07/98 12:55:56 rfbProcessClientNormalMessage: ignoring unknown
encoding type 3 
24/07/98 12:56:01 Client 10.0.0.1 gone 
24/07/98 12:56:01 Statistics: 
24/07/98 12:56:01   key events received 606, pointer events 1828
24/07/98 12:56:01   framebuffer updates 1024, rectangles 3960, bytes
827014 
24/07/98 12:56:01     copyRect rectangles 306, bytes 4896 
24/07/98 12:56:01     hextile rectangles 3654, bytes 822118 
24/07/98 12:56:01   raw bytes equivalent 10615278, compression ratio
12.912110 
xterm:  fatal IO error 101 (Network is unreachable) or KillClient on X
server "dppp48.buffnet.net:1.0" 
XIO:  fatal IO error 101 (Network is unreachable) on X server
"dppp48.buffnet.net:1.0" after 1532 requests (1522 known processed) with
0 events remaining.

-------------------

(note, at the end there, I just killed vncviewer on Win95).

OK, now, when I try to do the exact same thing without first connecting
my laptop to my ISP, I get this error log:

24/07/98 13:28:49 Xvnc version 3.3.2
24/07/98 13:28:49 Copyright (C) 1997-8 Olivetti & Oracle Research Laboratory
24/07/98 13:28:49 See http://www.orl.co.uk/vnc for information about VNC
24/07/98 13:28:49 Desktop name 'X' (laptop:1)
24/07/98 13:28:49 Protocol version supported 3.3
24/07/98 13:28:49 Listening for VNC connections on TCP port 5901
24/07/98 13:28:49 Listening for HTTP connections on TCP port 5801
24/07/98 13:28:49   URL http://laptop:5801
_X11TransSocketINETConnect: Can't connect: errno = 101
xrdb: Network is unreachable
xrdb: Can't open display 'laptop:1'
_X11TransSocketINETConnect: Can't connect: errno = 101
xset:  unable to open display "laptop:1"
_X11TransSocketINETConnect: Can't connect: errno = 101
xsetroot:  unable to open display 'laptop:1'
_X11TransSocketINETConnect: Can't connect: errno = 101
Fvwm-95: in function main: <<ERROR>> can't open display laptop:1
_X11TransSocketINETConnect: Can't connect: errno = 101
xterm Xt error: Can't open display: laptop:1
_X11TransSocketINETConnect: Can't connect: errno = 101
xterm Xt error: Can't open display: laptop:1

24/07/98 13:30:09 Got connection from client 10.0.0.1
24/07/98 13:30:09 Protocol version 3.3
24/07/98 13:30:15 Pixel format for client 10.0.0.1:
24/07/98 13:30:15   8 bpp, depth 8
24/07/98 13:30:15   true colour: max r 7 g 7 b 3, shift r 0 g 3 b 6
24/07/98 13:30:15 no translation needed
24/07/98 13:30:15 Using hextile encoding for client 10.0.0.1
24/07/98 13:30:15 rfbProcessClientNormalMessage: ignoring unknown encoding type 3
24/07/98 13:31:16 Client 10.0.0.1 gone
24/07/98 13:31:16 Statistics:
24/07/98 13:31:16   key events received 0, pointer events 39
24/07/98 13:31:16   framebuffer updates 10, rectangles 23, bytes 158192
24/07/98 13:31:16     hextile rectangles 23, bytes 158192
24/07/98 13:31:16   raw bytes equivalent 311702, compression ratio 1.970403

-----------------------------

So it seems like it does indeed make the connection, but then again, it
doesn't.  (as you can see, for my serial cable TCP/IP connection, I
assign 10.0.0.1 to the desktop, and 10.0.0.2 to the laptop).  What I
see on the Win96 machine's screen is the vncviewer window which
eventually settles as the black/white micro-hatched X background you
get with an X server.

Again, this message is being typed (offline from the internet) via a
remote X seesion, over the same serial line ppp connection (same session
even) as the connection that generated the above error messages.  So I
don't think it is a problem in my TCP/IP setup.

I made sure I had the right screen (e.g. ":1") entered into the dialogue
box when vncviewer started, and I tried both "laptop:1" and
"10.0.0.2:1" in the dialogue box (I have a laptop/10.0.0.2 entry in my
lmhosts file on the win95 machine).  I also tried seting the
environment variable DISPLAY to :1 in the xstartup script as suggested
in some of the mailing list archives.  All of this with no luck.

I suspect that this is an Xauth or a xhost problem.  I commented out
the Xauth line in the list of arguments fed to the server in the VNC
perl script.  But then again, I'm no Perl hacker, so I may not have
truly disabled Xauth.  however, I get the same results with or without
commenting out that argument.  I don't use Xauth on my local Xserver. 
I do use xhost when running a local X session.

Any ideas would be appreciated.  I can use the X viewer, but I'd rather
use VNC as it is a little faster, but more importantly, gives me my
choice of window viewers (with MIX, you are stuck with twm).

Please copy responses to jsundqui "at" buffnet.net, although I will surely
see that all suggestions and resolutions get posted here on this list.

TIA

Jon Sundquist




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