VNC User Guide

This powerful feature means you can set up the host computer so users can connect to it in different ways. For example, you could set up one instance of VNC Server so that connections to it are optimized for speed, and another so connections are optimized for security. VNC Server facilitates this using modes, each of which permits a different level of access to the host computer.

Note: To see how to start VNC Server in different modes, read Starting VNC Server.

For more information, read the section appropriate to the platform of the host computer below.

Windows

Under Windows, a host computer user with administrative privileges can start VNC Server in Service Mode. This means VNC Server runs, and users can connect, irrespective of whether or not a host computer user is logged on. By default, in order to connect to:

• VNC Server (Enterprise) or VNC Server (Personal), users must know the user name and password of a member of the Administrators group.

• VNC Server (Free) , users must know the VNC password.

In addition, or alternatively, a host computer user can log on and start VNC Server in User Mode. This means VNC Server runs, and users can connect, just while this host computer user is logged on (connections are terminated at log off). By default, in order to connect to:

• VNC Server (Enterprise) or VNC Server (Personal), users must know the user name and password of the currently logged on host computer user.

• VNC Server (Free) , users must know the VNC password.

Note: Microsoft User Account Control severely restricts users connected to VNC Server in User Mode from fully controlling a host computer running Windows Vista or later. The connected user loses mouse and keyboard control if a program requiring administrative privileges is run (this may or may not be preceded by a User Account Control prompt), and can only continue if a host computer user closes the program, or accepts the prompt.

Once connected to VNC Server in either Service Mode or User Mode, users have the same privileges (that is, access rights) on the host computer as the currently logged on host computer user. For more information, see Authenticating connections to VNC Server.

Because only one host computer user can log on to a Windows computer at a time, this means a maximum of two instances of VNC Server can run concurrently on a Windows host computer – one in Service Mode, and one in User Mode for the currently logged on host computer user. Both instances must listen on different ports; see Configuring ports for more information.

UNIX/Linux

Under UNIX/Linux, a host computer user can log on and start VNC Server in User Mode. In this mode, VNC Server runs attached to the console X Server session, which means that:

• A VNC Server icon and VNC Server dialog are displayed in order to help the host computer user configure VNC Server after it has started, if necessary.

• Connected users can access applications currently running on the host computer.

• VNC Server stops, and all connections are terminated, when the host computer user starting VNC Server logs off.

• By default, in order to connect to:

— VNC Server (Enterprise) or VNC Server (Personal), users must know the user name and password of the host computer user starting VNC Server.

— VNC Server (Free) , users must know the VNC password.

Once connected, users have the same privileges (that is, access rights) as this host computer user. For more information on privileges, see Authenticating connections to VNC Server.

Depending on the terms of your license, a host computer user can also, or alternatively, log on and start VNC Server in Virtual Mode. In this mode, VNC Server runs attached to a new virtual desktop, detached from the monitor and independent of the console. This means that:

• No VNC Server icon or VNC Server dialog can be displayed in order to help the host computer user configure VNC Server after it has started. To see how to work with VNC Server in this mode, read Working with VNC Server in Virtual Mode.

• Connected users cannot access applications currently running on the console of the host computer. Instead, an isolated workspace is provided. Note this powerful feature can help prevent conflicts; each user can be directed to connect to their own instance of VNC Server in Virtual Mode, and control a (virtual) desktop independently.

• VNC Server does not stop when the host computer user logs off. Users stay connected, and new users can connect. VNC Server must be explicitly stopped.

• By default, in order to connect to:

— VNC Server (Enterprise) or VNC Server (Personal), users must know the user name and password of the host computer user starting VNC Server.

— VNC Server (Free) , users must know the VNC password.

Once connected, users have the same privileges (that is, access rights) as this host computer user. For more information on privileges, see Authenticating connections to VNC Server.

Under UNIX/Linux, more than one host computer user can log on at a time. Each currently logged on host computer user can start VNC Server in either mode, and all instances, for all users, run concurrently. Note that all instances must listen on different ports; see Configuring ports for more information.

VNC Server can run as many times as your license permits. Each time a host computer user starts VNC Server (in either mode), the count of remaining desktops (that is, instances of VNC Server) is decremented. To see how many desktops are left, run the command vnclicense -check. For example, the output:

Licensed desktops: 5
Running desktops: 3
johndoe: 2
janedoe: 1

means that five VNC Server desktops are licensed to run concurrently on this host computer, and three are already running; two started by John Doe, and one by Jane Doe. Two are left to run.

Note: You can release licenses by killing desktops. To see how to do this, read Stopping VNC Server.

Mac OS X

Under Mac OS X, a user with administrative privileges can start VNC Server in Service Mode. This means VNC Server runs, and users can connect, irrespective of whether or not a host computer user is logged on. By default, in order to connect to:

• VNC Server (Enterprise) or VNC Server (Personal), users must know the user name and password of a member of the admin group.

• VNC Server (Free) , users must know the VNC password.

Once connected, users have the same privileges (that is, access rights) as the currently logged on host computer user. For more information on privileges, see Authenticating connections to VNC Server.

Depending on the terms of your license, a host computer user can also, or alternatively, log on and start VNC Server in User Mode. This means VNC Server runs, and users can connect, just while this host computer user is logged on (connections are terminated at log off). By default, in order to connect to:

• VNC Server (Enterprise) or VNC Server (Personal), users must know the user name and password of the host computer user starting VNC Server.

• VNC Server (Free) , users must know the VNC password.

Once connected, users have the same privileges (that is, access rights) as this host computer user. For more information on privileges, see Authenticating connections to VNC Server.

Under Mac OS X, providing Fast User Switching is turned on, more than one host computer user can log on at a time. Each currently logged on host computer user can start VNC Server in User Mode, and all instances, for all users, run concurrently. Note that all instances, in either mode, must listen on different ports; see Configuring ports for more information.

VNC Server can run as many times as your license permits. Each time VNC Server is started, the count of remaining desktops (that is, instances of VNC Server) is decremented. To see how many desktops are left, run the command /Library/VNC/vnclicense -check in a Terminal window. For more information on the message that is displayed, see the UNIX and Linux section above.