Monitoring session connections and disconnections

For a service application, such as a virtual channel server application, to monitor session connections and disconnections, you must register it with Remote Desktop Services. To register the application with Remote Desktop Services, store the name of the virtual channel server application in the registry by adding a subkey under the following location:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\TerminalServer\Addins

The subkey can have any name. It must have a REG_SZ value, Name, that contains the symbolic name of the application.

Name = AddinName

The maximum length of both the subkey and the value of Name is 99 characters.

The subkey must also have a REG_DWORD value that indicates the type of server application.

Type = AddinType

AddinType must be the following value.

ValueMeaning
3User-mode application, session space.

 

Registration of the service application takes effect only in sessions created after the registration was performed.

For each registered service application, Remote Desktop Services will signal a set of event objects when a client connects or disconnects from the session. Each virtual channel plug-in must register itself and create the notification events by calling CreateEvent. The names of these event objects adhere to the following format.

AddinName-Reconnect

AddinName-Disconnect

AddinName is the string specified in the Name value of the registry subkey under which the server application is registered. Creating these events under a session causes them to be created in a special per-session event directory. The event directory provides added security by preventing applications in other sessions from modifying the state of these events.

To control whether RECONNECT and DISCONNECT events are received on the server, you can place the RemoteControlPersistent flag in the registry under the following key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\TerminalServer\Addins\addinname

The flag enables or disables RECONNECT and DISCONNECT events from being signaled when a client session starts or stops. The syntax of the REG_DWORD value is the following.

RemoteControlPersistent = flag

The value of flag can be one or zero. Zero is the default value. If set to one, the service application will not be notified if the client session is started or stopped. If set to zero, a RECONNECT event is signaled when the client session starts, and a DISCONNECT event is signaled when the client session stops.

The previous event-object name format is still supported in Windows Server 2008 for backward compatibility. It is recommended that you use the newer Windows Server 2008 format because it is more secure.

The previous event format is as follows.

Global\AddinName-SessionId-Reconnect
 
Global\AddinName-SessionId-Disconnect

AddinName is the string specified in the Name value of the registry subkey under which the server application is registered. SessionId is the session identifier of a client session.

 

 

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