hi,

in /etc/kde3/kdm/kdmrc I did exactly what was suggested in the HowTo:
(relevant section)
Code:
[Xdmcp]
# Whether KDM should listen to incoming XDMCP requests.
# Default is true
Enable=true
# The UDP port on which KDM should listen for XDMCP requests. Do not change.
# Default is 177
Port=177
# File with the private keys of X-terminals. Required for XDM authentication.
# Default is ""
#KeyFile=/etc/kde3/kdm/kdmkeys
# XDMCP access control file in the usual XDM-Xaccess format.
# Default is "/etc/kde3/kdm/Xaccess"
Xaccess=/etc/kde3/kdm/Xaccess
# Number of seconds to wait for display to respond after the user has
# selected a host from the chooser.
# Default is 15
#ChoiceTimeout=10
# Strip domain name from remote display names if it is equal to the local
# domain.
# Default is true
#RemoveDomainname=false
# Use the numeric IP address of the incoming connection on multihomed hosts
# instead of the host name.
# Default is false
#SourceAddress=true
# The program which is invoked to dynamically generate replies to XDMCP
# DirectQuery or BroadcastQuery requests.
# If empty, no program is invoked and "Willing to manage" is sent.
# Default is ""
Willing=/etc/kde3/kdm/Xwilling
in /etc/kde3/kdm/Xaccess I also just uncommented the two lines listed in the HowTo.

I installed the vnc4server (deb-package).

The I modified /etc/xinet.d/Xvnc:

Code:
service Xvnc_user1
{
        type = UNLISTED
        disable = no
        socket_type = stream
        protocol = tcp
        wait = yes
        user = root
        server = /usr/bin/Xvnc
	server_args = :1 -geometry 1280x768 -depth 16 -query localhost -inetd -once -fp /usr/share/fonts/X11/misc,/usr/share/fonts/X11/misc/,/usr/share/fonts/X11/Type1/,/usr/share/fonts/X11/100dpi/,/usr/share/fonts/X11/75dpi/ -DisconnectClients=0 -AlwaysShared -IdleTimeout=0 passwordFile=/home/user1/.vncpasswd_user1 -extension XFIXES
        port = 5901
}

service Xvnc_user5
{
        type = UNLISTED
        disable = no
        socket_type = stream
        protocol = tcp
        wait = yes
        user = root
        server = /usr/bin/Xvnc
	server_args = :2 -geometry 1280x768 -depth 16 -query localhost -inetd -once -fp /usr/share/fonts/X11/misc,/usr/share/fonts/X11/misc/,/usr/share/fonts/X11/Type1/,/usr/share/fonts/X11/100dpi/,/usr/share/fonts/X11/75dpi/ -DisconnectClients=0 -AlwaysShared -IdleTimeout=0 passwordFile=/home/user5/.vncpasswd_user5 -extension XFIXES
        port = 5902
}

service Xvnc_user3
{
        type = UNLISTED
        disable = no
        socket_type = stream
        protocol = tcp
        wait = yes
        user = root
        server = /usr/bin/Xvnc
	server_args = :3 -geometry 1280x768 -depth 16 -query localhost -inetd -once -fp /usr/share/fonts/X11/misc,/usr/share/fonts/X11/misc/,/usr/share/fonts/X11/Type1/,/usr/share/fonts/X11/100dpi/,/usr/share/fonts/X11/75dpi/ -DisconnectClients=0 -AlwaysShared -IdleTimeout=0 passwordFile=/home/user3/.vncpasswd_user3 -extension XFIXES
        port = 5903
}

service Xvnc_user2
{
        type = UNLISTED
        disable = no
        socket_type = stream
        protocol = tcp
        wait = yes
        user = root
        server = /usr/bin/Xvnc
	server_args = :4 -geometry 1280x768 -depth 16 -query localhost -inetd -once -fp /usr/share/fonts/X11/misc,/usr/share/fonts/X11/misc/,/usr/share/fonts/X11/Type1/,/usr/share/fonts/X11/100dpi/,/usr/share/fonts/X11/75dpi/ -DisconnectClients=0 -AlwaysShared -IdleTimeout=0 passwordFile=/home/user2/.vncpasswd_user2 -extension XFIXES
        port = 5904
}

service Xvnc_user4
{
        type = UNLISTED
        disable = no
        socket_type = stream
        protocol = tcp
        wait = yes
        user = root
        server = /usr/bin/Xvnc
	server_args = :5 -geometry 1280x768 -depth 16 -query localhost -inetd -once -fp /usr/share/fonts/X11/misc,/usr/share/fonts/X11/misc/,/usr/share/fonts/X11/Type1/,/usr/share/fonts/X11/100dpi/,/usr/share/fonts/X11/75dpi/ -DisconnectClients=0 -AlwaysShared -IdleTimeout=0 passwordFile=/home/user4/.vncpasswd_user4 -extension XFIXES
        port = 5905
}

service Xvnc_user6
{
        type = UNLISTED
        disable = no
        socket_type = stream
        protocol = tcp
        wait = yes
        user = root
        server = /usr/bin/Xvnc
	server_args = :6 -geometry 1280x768 -depth 16 -query localhost -inetd -once -fp /usr/share/fonts/X11/misc,/usr/share/fonts/X11/misc/,/usr/share/fonts/X11/Type1/,/usr/share/fonts/X11/100dpi/,/usr/share/fonts/X11/75dpi/ -DisconnectClients=0 -AlwaysShared -IdleTimeout=0 passwordFile=/home/user6/.vncpasswd_user6 -extension XFIXES
        port = 5906
}

service Xvnc_student
{
        type = UNLISTED
        disable = no
        socket_type = stream
        protocol = tcp
        wait = yes
        user = root
        server = /usr/bin/Xvnc
	server_args = :7 -geometry 1280x768 -depth 16 -query localhost -inetd -once -fp /usr/share/fonts/X11/misc,/usr/share/fonts/X11/misc/,/usr/share/fonts/X11/Type1/,/usr/share/fonts/X11/100dpi/,/usr/share/fonts/X11/75dpi/ -DisconnectClients=0 -AlwaysShared -IdleTimeout=0 passwordFile=/root/.vncpasswd_student -extension XFIXES
        port = 5907
}
By convention I assigned a specific port to a specific user. Ports 5901 to 5906 are connected to VNC-password-files in the according user's home folder (apply chown userX:userX to it, so that the user can change his password using vncpasswd himself).
We have an additional VNC-account for a 'rightless' student - hence, his vncpasswd file is in the root-home.

This VNC-policy works really good, but unfortunately the GLX-extension is not supported by Xvnc. There is a project xf4vnc obviously supporting GLX, but there are no deb-packages and 64bit-binaries and I have not successfully compiled it, yet.

At the moment we are executing GLX-dependent applications via ssh -X, but this is not resumable like the VNC-policy is ...


>Anyway, if I could set this up, can I start these sessions (and the applications they have to run) at the boot time? - so, before the user logs in by vnc.

I cannot really tell you, but I think it could be possible to 'simulate' logins on the machine itself (maybe via a cron-job and some bash-scripts?). We do not need comparable features - our machine is something like a power-slave which we are using for complex and time-consuming model-calculations (therefore the resumable-aspect is quite important to us).

> Although this is Debian, I think there isn't many differences...
I think this, too!


cheers, lars