SMDI messages are used by the SMDI message server to generate either E-mail notifications of received messages which are forwarded to a user of the VMS or to supply VMS message status information to a voice message retrieval and forwarding system using IP messaging instead of SMDI FSK or PSK signaling. SMDI messages between a stored program controlled switching system, e.g., C.O. switch, and a voice message system are monitored by the SMDI message server of the present invention, e.g., by inserting a Tee into the SMDI link between the C.O. switch and VMS. The SMDI message server uses the directory number information and/or a message line identifier included in a received SMDI message to identify a subscriber or voice message retrieval and forwarding system which should be notified of the received SMDI message information.