A method is disclosed for notifying both the source and intended recipient of a classified electronic message transmitted via a computer network of a delivery restriction imposed by an insufficient classification level at the recipient's system. A required classification level is transmitted by the source of a classified electronic message in association with each classified electronic message in an indication of each classified electronic message is stored in an output log at the source system. Prior to permitting delivery of a classified electronic message, the required classification level is then compared to the classification level of the intended recipient. Delivery of a classified electronic message is automatically restricted in response to an insufficient classification level at the recipient's system and a status message is then transmitted to either or both the source and the intended recipient of the classified electronic message. In a preferred embodiment of the present invention, the recipient is automatically prompted to attempt to obtain a classification upgrade or forward the message to an alternate recipient in response to such restriction. Additionally, the method of the present invention permits an undelivered message to be destroyed by the source, the recipient, or the system in response to the failure of delivery.