By Jeanette Ray,2014-07-08 10:52
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VNC Server Free Edition 4.1 for Windows


    ; Requirements

    ; Installation

    o Upgrading from VNC Free Edition 4.0

    o User-Mode Operation

    o Service-Mode Operation

    ; Configuration

    o The Connections Options

    o The Authentication Options

    o The Inputs Options

    o The Sharing Options

    o The Desktop Options

    o The Capture Method Options

    o The Legacy & VNC 3.3 Import Options

    o Other Options

    ; Compatibility Notes

    o Windows 3.11 / Windows NT 3.51 / Windows 95

    o Windows 98 / Windows Me

    o Windows XP and Windows 2003 Server

    System Requirements Requirements:

    ; System hardware meeting OS requirements

    ; Windows-compatible graphics card ; Windows-compatible network card ; TCP/IP v4 network stack 1; Windows 98 1or Windows Me 2or Windows NT 4.0 Workstation / Server

    or Windows 2000 Professional / Server 3or Windows XP Professional / Home 3or Windows 2003 Server


    1. These platforms do not support secure settings

    2. Service Pack 3, 4, 5 or 6a is required on these platforms

    3. If Fast User Switching or Remote Desktop are used, then VNC Server will connect

    session zero to the console in order to allow it to be accessed. Other sessions cannot be

    accessed by VNC Server Free Edition 4.1.


    VNC Server Free Edition for Windows is installed as an optional component of the setup package. If VNC Server has been installed then a number of icons will be created for it under the Start Menu, at the location specified during installation (usually RealVNC).

    VNC Server for Windows is designed to run either in User-Mode, as a personal per-user server, or in Service-Mode, as a system service available whether or not there is a user logged in. The logged-on user can also choose to run their own personal User-Mode server alongside an existing Service-Mode server installed on the machine, provided that the two servers are configured to operate on different network port numbers.

    Upgrading from VNC Free Edition 4.0

    VNC Server Free Edition 4.1 retains full compatibility with VNC Server Free Edition 4.0, with respect both to command-line parameters and to registry configuration options. When installed on a system that has already been fully configured for VNC Server Free Edition 4.0, VNC Server Free Edition 4.1 will use the existing settings, without the need for reconfiguration. Using VNC Server in User-Mode

    If you are just trying out VNC, or wish to provide access to your desktop infrequently for support or collaboration purposes, then you may find it best to run VNC Server in User-Mode. During the installation, leave the tickboxes which refer to the VNC Server System Service unticked, to prevent VNC Server being installed in Service-Mode on your system.

When you want to use VNC Server, go to the VNC Server (User-Mode) program group

    (usually found under RealVNC in the Start Menu), and click on Run VNC Server. The VNC

    Server icon will appear in the system tray, to indicate that VNC Server is running.

    At this point, you probably want to configure your personal VNC Server settings for User-Mode. Right-click on the tray icon and select Options..., change the settings you want and click Apply

    or Ok. Note that you must at least configure the Authentication tab, otherwise you won't be able

    to connect in to your server - this is deliberately the case, to avoid accidentally opening up your computer to attacks.

    When you are finished with VNC Server, simply select Close VNC Server from the tray icon's


    Using VNC Server in Service-Mode

    If you intend to use VNC to provide remote access to a computer, you will probably prefer to install VNC Server in Service-Mode. In Service-Mode, VNC Server can allow remote connections even while the computer is locked or logged off. The server is configured once, rather than per-user, and the settings are secured if the host platform supports it.

    During the installation, tick each of the boxes which refer to the VNC Server System Service. This will cause the installer to present the VNC Server Options dialog, and to register and run the VNC Server Service.

    Note that you must at least configure the Authentication tab, otherwise you won't be able to

    connect in to your server - this is deliberately the case, to avoid accidentally opening up your computer to attacks.

    At this point, your VNC Server is running and you should be able to connect to it from a connected computer using VNC Viewer.

    If you need to reconfigure or stop your Service-Mode server, you will find links in the VNC

    Server (Service-Mode) program group of the Start Menu to achieve this. The VNC Server

    Properties dialog can also be accessed by right clicking on the VNC Server (Service-Mode)

    tray icon and selecting the Options... menu item.

    Configuring VNC Server

    VNC Server provides a number of options allowing its behaviour to be tailored to your needs. These are usually configured via the Options... dialog, although they can also be specified

    directly on the command-line of the WinVNC4 executable if required.

    The Options... dialog consists of a number of pages of options, grouped according to their function. The following documentation describes each option and the equivalent command-line parameters.

    When the Ok or Apply buttons of the Options... dialog are pressed, any changed settings are

    saved to the registry. Unless otherwise specified, changed settings take effect immediately. Connections

Accept connections on port

    PortNumber=(port number)

    If this option is ticked and the port number is non zero then VNC Server accepts

    incoming connection requests from clients on a particular TCP port. The standard VNC

    Display numbers, 0-99, correspond to TCP ports 5900-5999. VNC Server will accept

    connections on port number 5900 by default, which equates to VNC display number 0

    (zero). The port number for VNC Server to use can be set to any other available port

    number, even ones outside the 5900-5999 range.

    Disconnect idle clients after


    An idle client is one which has transmitted no keyboard or pointer events for more than a

    certain length of time. The VNC Server can be configured with a threshold, expressed in

    seconds, after which idle clients will be disconnected to conserve resources. If the

    threshold specified is zero seconds then connections will never timeout. The default idle

    timeout is one hour.

    Note that pointer and keyboard events received from clients will prevent their connection

    timing out even if the VNC Server is configured to otherwise ignore those events (see


Serve Java viewer via HTTP on port

    HTTPPortNumber=(port number)

    If this option is ticked and the port number specified is non-zero then VNC Server will

    accept incoming HTTP requests, allowing the Java VNC Viewer to be downloaded by a

    Java-aware web browser. The Options... dialog will attempt to adjust the HTTP port to

    match changes made to the VNC port number.

    Note that the HTTP port number cannot be set to the same value as that used for

    incoming VNC connections.

    Only accept connections from the local machine


    The LocalHost option tells VNC Server to only accept incoming connections from

    Viewers running on the local host computer. This is only normally used when

    connections are to tunnelled through a custom transport (e.g. serial line, custom wireless,

    etc) and will therefore appear to the TCP stack to originate from the local host. If VNC

    Server is configured to accept connections only via local loopback then the Hosts option

    is ignored.

    Access Control


    VNC Server can filter incoming connection attempts based upon the apparent IP

    addresses of their originators. Which IP addresses are allowed to connect and which are

    not is determined by the Hosts pattern. The pattern consists of a comma-separated list of

    IP address specifications, prefixed by an action. Each specification starts with an action,

    gives an IP address, and a subnet-style mask. The first specification to match the address

    of the new connection determines the action that will performed.

    Available actions are:

    ; +: Accept the connection

    ; ?: Query the local user to accept the connection.

    See also the QueryConnect Authentication option.

    ; -: Reject the connection.

    e.g. Hosts=+,+,-

    The pattern given above allows the computer with address to connect, as

    well as any computer in the 192.168.1 subnet. All other connections are rejected by the

    - term, which is actually redundant in this case - a connection will always be rejected if it

    doesn't match anything in the Hosts pattern.

    Note that IP addresses and masks are specified in Type-A (xxx.yyyyyyyyy), Type-B

    (xxx.yyy.zzzzzz) or Type-C (xxx.yyy.zzz.www) form. The specification 192.168 will

    therefore be interpreted as rather than as one might expect.

    The Hosts pattern can be edited more easily through the Access Control interface, which

    allows IP address specifications to be edited individually and moved up (to match first) or

    down (to match last) the list.


    The Authentication page allows you to configure the required mode of authentication and level of security of VNC connections. VNC Server Free Edition for Windows supports unauthenticated connections and classic VNC Password Authentication.

    No Authentication


    If your VNC Server is operating in a protected environment, such as a secure LAN or

    firewall-protected network, then you may wish to configure VNC Server to accept

    connections without requiring a username or password to be specified.

    We advise extreme caution when disabling authentication. Do not disable it unless

    you are absolutely sure that the host network is completely secure.

    VNC Password Authentication


    VNC Password Authentication allows a single password of up to 8 characters to be

    stored by VNC Server, which remote users must supply when prompted in order to


    The password to use can be configured by selecting Configure and typing the new

    password twice. On platforms which support it, the password (and all other configuration

    options) are protected using native operating system security methods, so that the

    password cannot be read or tampered with by other users.

    NT Logon Authentication

    NT Logon Authentication is not available in VNC Free Edition.

    Encryption: Always Off

    Encryption is not available in VNC Free Edition.

    Prompt local user to accept connections


    By default, VNC Server allows Viewers to connect as long as the correct username and

    password are supplied. QueryConnect allows an extra level of protection to be applied,

    requiring a local user to explicitly accept incoming connections.

    When QueryConnect is enabled, incoming connections are first authenticated in the

    normal way. If the user authenticates successfully then a dialog is presented on the

    server's desktop, displaying the IP address and username of the incoming connection, and

    requiring a local user to accept the connection.

    If the user does not accept the connection within a specified timeout then it is rejected. If

    an incoming connection requiring acceptance by the local user is received while an

    earlier connection is being queried then the second connection is automatically rejected,

    for security reasons.

    Connections from specific hosts or subnets can be configured to be queried via the Hosts

    configuration setting.

    Only prompt when there is a user logged on


    This option affects the behaviour of the QueryConnect option, if enabled. If this option is

    set then the local user will only be prompted to accept the incoming connection if they

    are logged in. If this option is not set then the local user will always be prompted,

    regardless of whether or not they are logged in.

    Note that it is not possible to reliably detect whether or not a user is logged in on some

    older Windows platforms. On these platforms, this option will err on the side of security

    and always prompt the local user.


    If QueryConnect is enabled then the Query Connection dialog will be displayed by

    default for ten seconds before automatically rejecting the connection. The timeout value

    can be modified by setting QueryConnectTimeout accordingly.


Accept pointer events from clients


    If this option is unticked then incoming pointer movements from all clients will be

    ignored, preventing any remote VNC Viewer from affecting the pointer of the VNC

    Server's desktop. This can be used to configure a server to become effectively view-only.

    Note that a client will still be deemed active for the purposes of the IdleTimeout setting if

    it is sending pointer events to the server, whether or not they are accepted. Accept keyboard events from clients


    If this option is unticked then incoming keystrokes from all clients will be ignored,

    preventing any remote VNC Viewer from typing into the VNC Server's desktop. This can

    be used to configure a server to become effectively view-only.

    Note that a client will still be deemed active for the purposes of the IdleTimeout setting if

    it is sending keyboard events to the server, whether or not they are accepted. Accept clipboard updates from clients


    If this option is unticked then incoming clipboard updates will be ignored from all clients.

    This option should be used when making a VNC Server effectively view-only, but may

    also prove useful to prevent clipboard changes made by clients from overriding the VNC

    Server's local clipboard when this would be undesirable or confusing.

    Send clipboard updates to clients


    This option, if unticked, prevents the VNC Server from informing clients of changes to

    its local clipboard contents. This can be useful when untrusted clients are to be allowed to

    connect to the VNC Server, since it prevents any private data being accidentally leaked

    via the clipboard.

    Allow input events to affect the screen-saver

    This option determines whether keyboard and mouse events received from VNC Viewers

    can cause the screen-saver to be hidden. This option is actually a system-wide setting and

    is not implemented by VNC Server itself, so there is no equivalent command-line option.

    Some older Win32 platforms do not support this option. It is recommended that this

    check-box be ticked, so that the screen-saver can be disabled by VNC Viewer input. Disable local inputs while server is in use


    The mouse and keyboard physically attached to the server computer can be disabled for

    the duration of a remote connection, preventing local users from interacting with the


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