VNC Authentication

VNC authentication is a popular topic of confusion amongst users. The most common pitfall is understanding the difference between the "Default" and "User" settings. The default settings should possibly be referred to as global settings. These are the settings inherited by VNC whenever it is started whether as a service or an application. However, VNC also allows for the assigment of unique VNC passwords for each Windows user on a machine. These passwords are set by logging in as a windows user, and setting the password in the user settings dialog box. Up to this point things are pretty straightfoward.

Lets go through the above diagram:
1. A user attempts to connect via VNC to a machine.
2. Is someone logged into the machine at either console or another remote connection?
3. If someone is logged in, then that user's settings are going to be used by the VNC service/application to authenticate the connecting client.
4. If no one is logged in, then the default or global settings will be used to authenticate the connecting client.

Of course if you do not want per user passwords then simply delete the registry key:
HKEY_Current_User\Software\ORL\WinVNC3

It should be noted that you are NOT required to specify passwords for each windows user. In this case you must always use the Show Default Settings dialog to modify the password. Not following this practice may leave you one day scratching your head trying to remember an old password.
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