VNC_related.md

TurboVNC

• When not working, getting log file
• "C:\Program Files"\TurboVNC\vncviewer.exe /help
• "C:\Program Files"\TurboVNC\vncviewer.exe server_name :display_number /loglevel 13 /logfile c:\TEMP\my_vnc.log

Started and Winsock (v 2) initialised
WinTab library not available # might be ignored
Buffer size expanded to 4352
Registered connection with app

• vncserver might be activated from putty. After vncserver is activated, if TurboVNC yields an error message of Could not open display :0, unset XDG_VTNR

mobaXterm

• VNC is allowed in the session menu
  • May use Connect through SSH gateway. This will not need firewall setup as ssh port is used
• To use ssh tunneling, display number(:1) shouldn't use in the ip menu. Instead change the port number such as 5900+1 = 5901
• Resolution is not changed dynamically as TurboVNC does. Adjust using -geometry when VNC is initiated or use xrandr command

   1920x1080     60.00*+
   1680x1050     59.95  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1440x900      59.89  
   1280x800      59.81  

• Then choose like xrandr -s "1920x1080_60" or xrandr -s "640x480_75" or xrandr -s 1600x1050
• If VNC is from RHEL6, virtualGL or vglrun might be necessary to run 3D graphics applications

Conflict with Anaconda

• Ref: https://unix.stackexchange.com/questions/469909/vncviewer-errorcould-not-connect-to-session-bus-failed-to-connect-to-socket-tm
• Error message: could not connect to session bus :failed to connect to socket/tmp/dbus-XXXXXXXX connection refused
• Cause: anaconda runs dbus-daemon and this may conflict with VNC server
• Solution: disable anaconda setup ($PATH) in the .bashrc and restart the terminal/vncserver command

when mouse grabbing crashes VNC (mobaxterm or turbovnc)

• Ref: neutrinolabs/xrdp#755
• May need to update rdp?
• Or run vncconfig
  • Disable 1) Also set primary selection 2) Send primary selection to viewers

vnc setup using systemd

• vncserver will be deprecated. Migration to system service is necessary in near future
• Ref: https://www.ibm.com/support/pages/how-configure-vnc-server-red-hat-enterprise-linux-8
• cp /lib/systemd/system/vncserver@.service /etc/systemd/system/vncserver@:3.service
  • No edit required
• vi /etc/tigervnc/vncserver.users
  • Add :3=USERname
• sudo -u USERname; vncpasswd; # or the USERname has configured vncpasswd already
• sudo systemctl start vncserver@:3.service
• sudo systemctl enable vncserver@:3.service # now restarts at reboot
• As shown above, a user will not be able to launch vnc service anymore. Must be registered by admin and the display port will be given