VNC User Guide

Preventing particular connections to VNC Server

You can prevent particular users connecting to VNC Server. You can either:

•  Prevent connections from particular client computers. See Preventing connections from particular client computers.

•  Prevent particular users connecting. See Preventing particular users connecting.

Note: You can prevent all users connecting to VNC Server. For more information, see Preventing connections to VNC Server.

Preventing connections from particular client computers

You can prevent all connections originating from particular client computers by filtering the network addresses of those client computers.

Note: If you filter network addresses, users can no longer enter host computer IPv6 network addresses in order to connect to VNC Server (even from an authorized client computer).

To filter network addresses, open the VNC Server - Options dialog. More on this dialog. On the Connections tab, click the IP Filter button:

By default, connection requests are accepted from all client computers. To reject connection requests from a particular client computer, click the Add button:

Specify the network address, or range of addresses, in IPv4 format, and then choose one of the following options.

Note that if you do filter network addresses, the order of rules in the VNC Server - Filter Rules dialog is important. The first matching rule determines what happens to connection requests from a particular client computer. For example, if a rule rejecting a client computer is encountered before one accepting it, then all connection requests from that client computer will be rejected. You can move rules up and down in the dialog using the arrows.

By default, the Default rule accepts connection requests from all client computers. You can change this so that it rejects or queries all connection requests instead. To do this, select the Default rule, and click the Edit button. Note this rule is always last in the dialog.

Preventing particular users connecting

You can prevent a particular user connecting by causing a connection prompt to appear on the host computer’s desktop:

A connection prompt enables a host computer user (if one is present), or an already-connected user, to identify the connecting user and either accept the connection request, allow ‘view only’ access to the host computer, or reject it. If no response is received within ten seconds, then the connection request is automatically rejected. Note that if you are setting up VNC Server on your own computer for remote access then enabling this feature may prevent you connecting.

Note: In some circumstances, certain users connecting to VNC Server (Enterprise) or VNC Server (Personal) are able to bypass connection prompts. To submit these users to prompts, revoke the Connect without accept/reject prompt VNC permission. For more information, see Customizing VNC permissions.

To display connection prompts, open the VNC Server - Options dialog. More on this dialog. On the Connections tab, choose Show accept/reject prompt from the When VNC Viewers connect dropdown:

In certain circumstances, you may be able to conditionally display connection prompts:

•  For VNC Server in Service Mode (Windows and Mac OS X), choose Show prompt only if user logged on in order to automatically accept connections when no host computer user is currently logged on (and therefore unlikely to be present). Note that at least one newly-connected user must then log on to the operating system of the host computer in order to continue. Subsequently, connection prompts are displayed again, for this user to accept or reject.

•  For VNC Server in Virtual Mode (UNIX/Linux), choose Show prompt only if user connected to automatically accept the first connection (since no host computer user can be ‘present’ at a virtual desktop). Subsequently, connection prompts are displayed again, for this user to accept or reject.

For more information on notifications, see Notifying when users connect.