- User Guide
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You can enable particular users to connect to VNC Server without specifying a password, bypassing VNC Server’s authentication mechanism altogether.
Note: You can turn authentication off for all users if you consider it safe to do so. For more information, see Turning authentication off.
You can either:
• Establish a reverse connection to a particular client computer. See Establishing a reverse connection.
• Allow a particular user to connect as a Guest. See Allowing a Guest to connect. Note this remote control feature is not available in VNC Server (Free).
Clearly, you should only establish reverse connections to client computers with trustworthy potential users, and only allow trustworthy users to connect as Guests. If you are setting up VNC Server on your own computer for remote access, note that a user must be present at the host computer for either of these features to work.
You may be able to establish a reverse connection to a particular client computer, bypassing the authentication mechanism specified by VNC Server.
Note: The client computer must be running Listening VNC Viewer. For more information, see Starting Listening VNC Viewer.
Note this feature is also useful if the host computer is protected by a firewall that cannot be configured to allow network communications, or by a router that cannot be configured to forward network communications, thus preventing incoming connections. In a reverse connection, network communications from the host computer are outgoing.
To establish a reverse connection:
1. Open the VNC Server shortcut menu. More on this menu.
2. Select Connect to Listening VNC Viewer:
3. If you are connecting:
— Within a private network, enter the network address of the client computer itself. If you do not know what this is, ask a client computer user to run a command such as ipconfig (Windows) or ifconfig (Linux and Mac OS X).
— Over the Internet, enter the network address of a router protecting the client computer. If you do not know what this is, you can ask a client computer user to visit www.whatismyip.com.
For more information on private and public networks, start with Connecting within a private network.
Listening VNC Viewer listens for reverse connections on port 5500. If a reverse connection fails, it may be because the client computer is protected by a router and/or a firewall and these have not been configured to allow access to Listening VNC Viewer on port 5500. For more information on this, and connection issues in general, see Troubleshooting connection.
When a reverse connection is established, the desktop of the host computer is displayed on the client computer in exactly the same way as it is for VNC Viewer. A Listening VNC Viewer user can control the host computer exactly as a VNC Viewer user does. For more information, see Chapter 3, Using VNC Viewer.
You can allow a particular user to connect to VNC Server (Enterprise) or VNC Server (Personal) as a Guest, bypassing the authentication mechanism. A Guest typically connects infrequently, or for a short period of time.
Note: VNC Server (Free) does not support guest connections. Upgrade the host computer to VNC Server (Enterprise) or VNC Server (Personal) if flexibility is important to you.
To enable Guests to connect:
1. Open the VNC Server - Options dialog. More on this dialog. On the Connections tab, select an alternative to the default None option from the Guest access dropdown:
To give users:
— The ability to remote control the host computer, select Interactive.
— View only access, select View-only. Any keypresses or mouse movements made by the user will have no effect.
2. Turn on the Guest Login option on the VNC Server shortcut menu. More on this menu. A tick appears:
Note: If the Guest Login menu option is turned off, Guests cannot connect. Note that other connected users can turn this menu option on and off. When VNC Server starts, Guest Login is turned off by default.
3. Inform users that they must enter Guest in the Username field of the VNC Viewer - Authentication dialog. More on this dialog. The Password field, however, should be left empty.
When a Guest connects, a connection prompt appears on the host computer:
A host computer user must accept the connection request within ten seconds or it will be automatically rejected. For more information on connection prompts, see Preventing particular users connecting.