How to Enable and Disable VNC server password authentication in cent os

You can switch between password and non password mode by:

# vi /etc/X11/xorg.conf  (enable password)

[..]

    #Option "SecurityTypes" "None"

    Option "SecurityTypes" "VncAuth"

    Option "UserPasswdVerifier" "VncAuth"

    Option "PasswordFile" "/root/.vnc/passwd"

[..]

# vi /etc/X11/xorg.conf  (disable password)

[..]

    Option "SecurityTypes" "None"

    #Option "SecurityTypes" "VncAuth"

    #Option "UserPasswdVerifier" "VncAuth"

    #Option "PasswordFile" "/root/.vnc/passwd"

[..]

Restart X for change to take effect:

# init 3   (wait a few seconds - )

# init 5

after enabling the password: 

You should be able to type ”vncpasswd” from the terminal as root. This will enable you to type in a new password for the VNC connection.