C#

IDictionary props = new Hashtable();
int portNumber = 9876;
props["port"] = portNumber;
props["typeFilterLevel"] =
   System.Runtime.Serialization.Formatters.TypeFilterLevel.Full;
try
{
   ChannelServices.RegisterChannel(new TcpChannel(props, clientProvider, serverProvider));
}

public Server()
{
	BinaryClientFormatterSinkProvider clientProvider = null;
	BinaryServerFormatterSinkProvider serverProvider = new BinaryServerFormatterSinkProvider();
	serverProvider.TypeFilterLevel = System.Runtime.Serialization.Formatters.TypeFilterLevel.Full;
	
	IDictionary props = new Hashtable(); 
	int portNumber = 5050;      
	props["port"] = portNumber;        
	props["typeFilterLevel"] = System.Runtime.Serialization.Formatters.TypeFilterLevel.Full;  
	try      
	{        
		ChannelServices.RegisterChannel
			(
			new TcpChannel(props, clientProvider, serverProvider)
			);         
	}
	finally
	{}

	string url = "tcp://localhost:5050/RemoteObject";
		
	Type serverType = typeof(RemoteObject);
	RemotingConfiguration.RegisterWellKnownServiceType(
		typeof(RemoteObject), "RemoteObject", 
		WellKnownObjectMode.Singleton);

	RemoteObject rem = (RemoteObject)Activator.GetObject(serverType,url);
	rem.CloseSockets = new RemoteObject.CloseSocketsDelegate( this.CloseSockets );
}

CloseSockets.  The three clients might not even been in a state where they are ready to handle the delgate (ie. delegates are not interupts!).  Also consider that in many networks, the machine requesting/answering is not the machine making the request or answering.  Another machine is doing the NAT/proxy/other network manipulation.  Although it might work for "localhost" you can easily run into problem traversing even intranets.  Again three clients are connected to the server but the server only sees one IP for each of the client.  How does the server know which machine on the "other side" of the NAT/proxy/firewall to contact?<br />
<br />
In general, a client/server network design shouldn't rely on the client telling the server to close socks.  Strong server systems never rely on its client communication protocol for run state instructions.  Clients telling servers "tell me the answer to 3 + 4" is okay.  Clients telling servers to "cut network connections" is bad.  I emplore you to consider another way to do whatever it is you are attempting to do.