** HKEY_LOCAL_MACHINE\Software\ORL\WinVNC3 : Options specified in this section are not overridable

DebugMode : 1:debug 2:file (WinVNC.log) 4:console

DebugLevel : 0-20 the higher the number the numerous and detailed messages are logged

DisableTrayIcon : Setting this entry to 1 remove the tray icon

LoopbackOnly : Setting this entry to 1 causes WinVNC to accept loopback connections

MSLogonRequired : Setting this registry entry to 1 force to use of ms-logon and disable vnc passwd checking

AllowLoopback : Setting this registry entry to 1 will cause local-loopback connections to be allowed.  Setting it to zero will filter out such connections

AuthRequired : Setting this registry value to zero will disable null-password checking by WinVNC

ConnectPriority : By default, all WinVNC servers will disconnect any existing connections when an incoming, non-shared connection is authenticated.  This behaviour is undesirable when the server machine is being used as a shared workstation by several users or when remoting a single display to multiple clients for vewing, as in a classroom situation.
ConnectPriority indicates what WinVNC should do when a non-shared connection is received:
0 = Disconnect all existing connections.
1 = Don't disconnect any existing connections.
2 = Refuse the new connection.
3 = Refuse all new connection (shared and non shared)

AuthHosts : The AuthHosts setting is, unlike the other settings, a REG_SZ string. It is used to specify a set of IP address templates which incoming connections must match in order to be accepted. By default, the template is empty and connections from all hosts are accepted. The template is of the form: 
+[ip-address-template]
?[ip-address-template]
-[ip-address-template]
In the above, [ip-address-template] represents the leftmost bytes of the desired stringified IP-address. For example, +192.168 would match both 192.168.12.10 and 192.168.14.2. Multiple match terms may be specified, delimited by the ":" character. Terms appearing later in the template take precedence over earlier ones. e.g. -:+192.168: would filter out all incoming connections except those beginning with 192.168. Terms beginning with the "?" character are treated by default as indicating hosts from whom connections must be accepted at the server side via a dialog box. The QuerySetting option determines the precise behaviour of the three AuthHosts options.

**HKEY_LOCAL_MACHINE\Software\ORL\WinVNC3\Default : Options specified here are overridable ny the user specific settings

**HKEY_LOCAL_MACHINE\Software\ORL\WinVNC3\<username> : These override the local default user settings. If there is no current user, the username SYSTEM will be used.

**HKEY_CURRENT_USER\Software\ORL\WinVNC3: These are only read if AllowProperties has not been set to zero

AllowShutdown : If this is set to zero, the user is not allowed to close down WinVNC.

AllowProperties : If this is set to zero, the user is not allowed to view the properties dialog and hence cannot change any settings, including the password.  Note that this stops all global per-user settings. A valid password must therefore be in force before using this setting, generally in the local default-user setting.

AllowEditClients : WinVNC will include the Add New Client and Disconnect All Clients options on the tray icon menu. This option causes these options to be disabled, preventing users from connecting out to listening viewers, or from disconnecting existing viewers.

TurboMode : Less Accuracy in screen changes detection but more Speed

FileTransferEnabled : If this is set to 1, FileTransfer is enabled so conncted viewers can use it

BlankMonitorEnabled : If this is set to 1, a connected viewer can blank the Server's Monitor

LocalInputsDisabled : if this is set to1, the viewer block the server input

DefaultScale : The server can set its default Scale (the division factor of the screen that is sends to connected viewers)

DSMPlugin : The filename of the DSM Plugin to be used to modify the communication data stream (PluginName.dsm)

UseDSMPlugin : If set to 1, the DSM Plugin is used

SocketConnect : This corresponds to the 'Accept Socket Connections' option in the properties dialog box

HTTPConnect : Corresponds to the Enable Java Viewer setting in the Properties dialog

XDMCPConnect : Experimenteal, start external xdmcp listener

AutoPortSelect : Causes WinVNC to select the first available display number automatically. Corresponds to the 'Auto' checkbox in the Properties dialog

PortNumber : specifies the port number to be used for VNC. You will need to disable AutoPortSelect to use this.

HTTPPortNumber : Specifies the port number to be used for the Java Viewer setting in the Properties dialog.

IdleTimeout : This setting tells WinVNC how many seconds a connected VNC client may remain idle for (no input events or update requests) before being disconnected. If this setting is not specified or is set to zero then no timeout is enforced.

RemoveWallpaper : Indicates whether or not WinVNC should remove the user's background wallpaper when an incoming connection is made. It is necessary to reconnect in order for this setting to take effect.

QuerySetting : The QuerySetting allows individual users to tailor the degree of paranoia expressed by the per-machine AuthHosts setting. It is a DWORD value ranging from zero (maximum availability) to four (maximum security). The following table indicates how the value affects the AuthHosts behaviour:
0 - +:Accept, ?:Accept, -:Query
1 - +:Accept, ?:Accept, -:Reject
2 - +:Accept, ?:Query, -:Reject [Default]
3 - +:Query, ?:Query, -:Reject
4 - +:Query, ?:Reject, -:Reject
By default, value 2 (Obey AuthHosts) will be assumed.

QueryTimeout : The QueryTimeout setting indicates the number of seconds for which the Accept Connection dialog (see AuthHosts and QuerySetting options) will be displayed before rejecting the incoming connection automatically.

InputsEnabled : Corresponds (inversely) to the 'Disable Remote keyboard and pointer' option in the Properties dialog box

LockSetting : WinVNC can be made to take actions when a viewer disconnects by setting this value as follows:
0 - none
1 - lock workstation on disconnect (Windows 2000/XP Only)
2 - logoff on disconnect

PollUnderCursor :A variation on Poll Foreground Window, this option causes the window under the mouse cursor to be polled for changes. Both options may be enabled simultaneously if required. PollForeground: Polling only the currently selected window for changes is less CPU intensive than full-screen polling and often gives similar results, for example when using the Command Prompt, which is not normally compatible with WinVNC

PollFullScreen : When the Video Driver is not used, some applications are incompatible with the methods currently used in WinVNC to trap screen updates. For this reason, it is sometimes useful to be able to poll the entire screen in order to check for changes. Note that the PollFullScreen of Ultr@VNC is really fast even without Video Hook Driver (not too much at the expense of accuracy) compared to the others VNCs. So it is recommended to have this option selected anyway (set to 1).

OnlyPollConsole : When this option is set, the only windows which will be ever be polled are Command Prompts. This works well in conjunction with Poll Window Under Cursor, to use polling only when the cursor is over a console window.

OnlyPollOnEvent : When this option is set, the screen will only be polled for updates when a mouse or keyboard event is received from the remote client. This is provided for low bandwidth networks, where it may be useful to control how often the screen is polled and changes sent.

EnableDriver : If this is set to 1 , the Video Driver (w2k >) or the ddihook (9.x) is used.  This value is ignored if low bandwidth is detected (modem)

EnableHook : If this is set to 1, the Hookdll is used to detect screen updates

EnableVirtual Driver: (old) from experimental driver. Outdated.