VNC User Guide - RealVNC

Chapter 6: Setting Up VNC Server
Running multiple instances of VNC Server
Under any platform, and providing your license entitles you to do so, you can run more than one instance of
VNC Server on a host computer.
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 on page 73.
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 on page 98.
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 on page 88 for more information.
78 VNC User Guide