topic Re: dislay problem in Operating System - Linux

dislay problem

Fadia Almarei — Mon, 05 Jul 2004 03:01:57 GMT

Hi All
i think i have an X display problem on my linux 9 system , that i can not open my VNC veiwer for the linux server from a win2k system , i do not know how to check the problem and how to solve it.

BR,
Fadia

Re: dislay problem

Fred Ruffet — Mon, 05 Jul 2004 04:13:57 GMT

Fadia,

Running VNC as a server on linux, you will need to have two things :
. VNC service running (as root, "service vnc start" or something like that)
. 5900 port open. It is the default port. If you do a little port restrictions, you may have lock it.

Regards,

Fred

Re: dislay problem

Fadia Almarei — Mon, 05 Jul 2004 04:28:33 GMT

thanks Fred
by how can i check that the port is opened for it or not , i take a look at the /etc/services but i can not recognize any thing

Re: dislay problem

Matt Palmer_2 — Mon, 05 Jul 2004 04:36:34 GMT

Hi,

to see if port is open you could look at the output from a netstat, you could also try telnet localhost 5900, and see what answers, and you could also use nmap or nmap-fe if you possess a GUI to do a portscan on your host and see what ports you have open.

Also are you sure of the syntax you are using to initiate the connections, are you specifying the screen number for the VNC client??

hope this helps

regards

Matt

Re: dislay problem

Fadia Almarei — Mon, 05 Jul 2004 05:17:15 GMT

Dear Matt
whould you explain more deeply, i do not really understand what to do and how to check

Re: dislay problem

Fred Ruffet — Mon, 05 Jul 2004 07:56:27 GMT

Fadia,

Matt proposes 3 ways to see if port is open :
. from the machine, type "netstat -tan". It will give you the tcp ports the machine is listening on. If you don't have 5900, VNC server is not launched, or not on common port.
. Try to issue "telnet host 5900". If a communication is established on port 5900, somebody's listening...
. Use a linux utility called nmap. "nmap host" gives you the open ports on host.

Note that if you run this tests from the macine successfully the ports are open. If you run it unsuccessfully from distant machine, FW is probably blocking you.

If you want to run tests from distant host, run tests from a machine in the same subnet, and physically near from the one VNC doesn't work.

Regards,

Fred

Re: dislay problem

Matt Palmer_2 — Mon, 05 Jul 2004 08:48:14 GMT

Fred is spot on that is exactly what I am saying. Also, if you use nmap-fe behind a firewall you need to check the'dont ping' box.

then enter the hostname and click scan.

once you have decided if 5900 is responding, then you need to specify the 'screen' number to the client.

HTH

Matt

Re: dislay problem

Fred Ruffet — Mon, 05 Jul 2004 09:03:45 GMT

Fadia, just seen your precedent post on the same problem...

When you connect from VNC client to Linux server, a new display is created for the session (i.e : you will connect to host:x.0 where x may not be 0). To confirm the problem resides here, you may need to put a "xhost +" command on display opening. This may be done within a file called /etc/X11/xdm/GiveConsole (This is only a test, and you must not leave this).

On the other hand, it could still be a FW problem, so can you try to connect from a machine in the same subnet where the server is ?

One other point : You said "linux 9". I use slackware 9. This is also a linux distribution, in its 9th release, but not redhat... Redhat is not linux.

Regards,

Fred

Re: dislay problem

Chris Eubank — Tue, 27 Jul 2004 17:04:47 GMT

Fadia,

RealVNC (www.realvnc.com) has really good documentation on how to install their latest version. I haven't tried using it with any other release other than Fedora Core2, but the newer version will allow you to connect to screen :0.

If you have an older version of VNC, then it is likely that you should be pointing your desktop VNC to port 5901, not 5900. so it would be "IP.AD.DR.ESS:5901".

You should also have run "vncpasswd" as the user you want to run the VNC server as, and then run "vncserver :1" after that.

Hope this helps!

Re: dislay problem

Petr Simik_1 — Thu, 29 Jul 2004 05:44:05 GMT

check .vnc directory there is a log file of your server.
Do you specify correctly display number?
hostname:1 <- according to your server setting??
Can you access server by ping?

Re: dislay problem

Adrien Carlyle_1 — Wed, 04 Aug 2004 08:19:48 GMT

i would also like to comment on "linux 9"
linux is currently at version 2.4.xx stable release, and the unstable next get realease is only linux 2.6.xx

there are a few GNU/linux distributions that have 9 releases, MANDRAKE REDHAT SLACKWARE.

all GNU/linux distributions are wrongfully referred to as "linux" and while i cant change the world, education is never a bad thing...