LinuxSA Mailing list archives

  From: Jake Hawkes <jake@eclectic.com.au>
  To  : Edward Sawma <e-sawma@nwu.edu>
  Date: Mon, 29 Nov 1999 15:01:19 +1030

Re: Xvnc problem

brief thingy about xwindows.

client <---> server

the server is what displays the stuff to your screen, the client is what
does the clever bits.

in most cases, people will have the client and the server running on the
same machine. e.g. the client (netscape, gnome, kde, xterms...) talks to
the server (X11).

the X window system was origionally designed to be used in a "thin
client" situation. eg., big grunty UNIX box running all the clients for
a computer pool full of Xterms (boxs with keyboard, mouse, screen videa
and network card). The server ran all the clients, and the Xterm ran all
the servers.

So, when you log onto a server, and type "netscape" at the prompt, it
looks at your DISPLAY variable and from this decides where to send the
Xwindows commands (command like draw window, accept mouse click etc). If
this is not set, I think it defaults to the local machine. If there is
no server waiting, you get _X11TransSocketINETConnect: Can't connect:
errno = 111.

So in times past, the solution was to make sure that the DISPLAY
variable was set. In fact, I have a script in my login that does this
for me. It look like this:
#!/bin/tcsh
setenv DISPLAY ${REMOTEHOST}:0.0

now, my knowledge breaks down a bit when it comes to xauth. Xauth the
program is used to manipulate Xauthority (security) key data. the
Xauthority protocol is used by the Xserver to communicate with the
client machine to restrict who can connect.

> seems that the tag "-auth /root/.Xauthority" that the startup script
> "vncserver" uses when executing Xvnc, is causing the problem.  When it is

so, this would seem that you are specifiying the program to use the file
/root/.Xauthority as the place to look for the Xauthority key data. By
removeing this line, I assume that would disable the use of xauth, but
you may need to read up on that client.

the xhost + command tells the server to allow connections from any
machine. Anywehere. the xhost system is another (weaker) security thing. 

I think you will find though, that if you specify a program to run using
xauth then it will override anything xhosts has to say.

other things to check:
the server should have an environment variable:

DISPLAY xxx.xxx.xxx.xxx:0.0 (xxx's is the IP address of the machine
running the *server* (see above)

in most cases though, you'll be running the server and client on the
same box, so:
DISPLAY :0.0 will be fine.




--
Jake Hawkes, B. Eng (CSE)
e-mail: jake@eclectic.com.au

http://www.projecteclectic.com

Chaos, panic, & disorder -- my work here is done.

-- 
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