PROTOR Knowledge Base

PROTOR Redhat : Installing VNC Server on Redhat 7.2

Author:	Don Davies
Date:	28-Apr-2002

PROTOR uses VNC extensively to provide remote access to the PROTOR Host from PCs running either Windows or Linux on the network. In order to use VNC the VNC server (Xvnc) must be installed and configured. Each remote PC which wishes to connect must then have the VNC client software installed. The following notes describe how to install and setup the VNC server on a PROTOR Host running Redhat 7.2

Login as root. Check if VNC server is already installed by command which Xvnc If the package has already been installed then the location of the server will be reported, typically /usr/bin/Xvnc.
If the server is not has installed then install the RPM from RedHat installation disk #1 using a suitable package manager or use the command.

                rpm --install --replacefiles --nodeps
                      /mnt/cdrom/RedHat/RPMS/vnc-server*.i386.rpm

            Note. The current release level of the VNC server for RedHat 7.2 is
            vnc-server-3.3.3r2-18.i386.rpm

Add the following lines to the end of /etc/services file.

       # VNC Servers
       vnc-1024x768x16  5900/tcp
       vnc-800x600x16   5901/tcp

Create a file called vnc in the directory /etc/xinetd.d/ which contains the following:

      service vnc-1024x768x16
      {
        flags = REUSE
        protocol = tcp
        socket_type = stream
        wait = no
        user = nobody
        server = /usr/bin/Xvnc
        server_args = -inetd -query localhost -once -geometry 1010x738 -depth 16
        log_on_failure += USERID
        disable  = no
      }
      service vnc-800x600x16
      {
        flags = REUSE
        protocol = tcp
        socket_type = stream
        wait = no
        user = nobody
        server = /usr/bin/Xvnc
        server_args = -inetd -query localhost -once -geometry 790x572 -depth 16
        log_on_failure += USERID
        disable = no
      }

Note that the service names ( vnc-1024x768x16 , vnc-800x600x16 ) must match the names entered into /etc/services. A large number of entries may be created for specific screen sizes and colour depths. Note that in the examples above the actual geometries configured for PROTOR have been reduced from the full screen size to allow for window decorations.
In the above examples when you wish to connect with a screen size of 1024x768 and depth 16 then connect using port 5900 or if using vncviewer then connect using <hostname>:0. Use port 5901 or <hostname>:1 to connect with 800x600 and depth 16.
You now need to restart xinetd. Use the command:

       service xinetd restart

In order to connect from a remote X-server or X-terminal you now need to enable XDMCP (X Display Manager Control Protocol ) both in general and for the specific Display Manager you are currently using (either xdm , gdm or kdm ).
Firstly you must edit the file /etc/X11/xdm/xdm-config . Ensure the line (usually the last line ) is commented out.

        !DisplayManager.requestPort:    0

Now edit the file XDMCP control file /etc/X11/xdm/Xaccess . Uncomment the following line.

         !*     # any host can get a login window

Enable XDMCP for gdm by running the configuration program gdmconfig. Enter Expert mode and the XDMCP page. Ensure that XDMCP is enabled. The port number should already be set to 177. Alternatively edit the file /etc/X11/gdm/gdm.conf .
Enable XDMCP for kdm by editing the file /etc/kde/kdm/kdmrc. There is a [Xdmxp] section in this file. In this section edit the line:

          Enable = false
   to be
          Enable = true

and uncomment the line

          Port = 177

You now need to restart the X-window system. Probably easiest is to use init 3 followed by init 5 or alternatively perform a complete system shutdown and restart.

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