Tutorial VNC Server on Linux Debian Bookworm

To set up an X11 VNC server on Debian, the recommended package is x11vnc, which provides remote access to an existing X session. Alternatively, you can use other VNC servers like TightVNC or TigerVNC to create a new, virtual X desktop session. 

Using x11vnc to Access the Current Desktop 

x11vnc is ideal for remote assistance or accessing the same desktop visible on the physical monitor. 

Installation:

sudo apt update && sudo apt install x11vnc

Configuration and Usage:

Set a VNC password (optional but highly recommended):

x11vnc -storepasswd

This creates a password file, typically located at ~/.vnc/passwd.

Run the server:

To run it in your current terminal session, use:

x11vnc -display :0

You will likely need to use the -auth option or set the XAUTHORITY environment variable to grant x11vnc permission to connect to the X server. 

x11vnc -auth -forever -loop -noxdamage -repeat -rfbauth ~/.vnc/passwd -rfbport 5900 -shared ncache_cr -ncache 10

-forever: keeps x11vnc running after a client disconnects.

-shared: allows multiple clients to connect simultaneously.

Connect securely via SSH tunnel (recommended over direct connection):

VNC does not use secure protocols by default. On your local machine, set up an SSH tunnel and then point your VNC client to localhost:5900:

bash

ssh -L 5900:localhost:5900 -C -N -l your_username your_server_ip

Once the tunnel is active, use a VNC viewer to connect to localhost:5900. 

Using TightVNC (or TigerVNC) for a Virtual Session 

If you don't have a physical monitor attached or want to run a separate, independent graphical session, tightvncserver is a common choice. 

Installation:

sudo apt update

sudo apt install tightvncserver xfce4 xfce4-goodies dbus-x11

Installing a lightweight desktop environment like Xfce is often necessary on a server without a default GUI. 

Configuration and Usage:

Set a VNC password:

vncserver

Follow the prompts to set a password and optionally a view-only password. This command also creates initial configuration files and starts a server instance (e.g., on display :1, port 5901).

Stop the VNC instance to configure its startup script:

vncserver -kill :1

Configure the xstartup file to use your chosen desktop environment (e.g., Xfce). Back up the original file, then edit the new one:

mv ~/.vnc/xstartup ~/.vnc/xstartup.bak

nano ~/.vnc/xstartup

Add the following lines to the ~/.vnc/xstartup file:

#!/bin/bash

xrdb $HOME/.Xresources

startxfce4 &

Save the file and make it executable:

chmod +x ~/.vnc/xstartup

Start the VNC server:

vncserver

It will start a new session on port 5901 (display :1).

Connect from a client using the same SSH tunneling method as with x11vnc, but ensure the ports match the VNC server instance (e.g., 5901).