property Socket: TIdIOHandlerSocket;

Socket is a read-only TIdIOHandlerSocket property that represents the socket-based IOHandler for the connection to the peer. Socket is updated when the IOHandler for the connection is assigned in the protected SetIOHandler method. 

Socket can be used to access the properties and method specific to the socket handle in TIdIOHandlerSocket. 

Please note that Socket will contain the value Nil if an IOHandler is assigned that does not derive from TIdIOHandlerSocket.