Data transmission method, a data transmission program and a data transmission server

A computer-readable medium storing a data transmission program for a computer that transmits data received from a client to a destination, the data transmission program causing said computer perform operations, comprising:

• storing client identification information and user identification information uniquely determined by authentication ID and password authenticated by Post Office Protocol (POP);
• determining whether the client identification information of the client which transmits the data and sender user identification information of the user are stored in correspondence to each other;
• and
• controlling not to transmit the data received from said client to the destination when determined that the client identification information of the client which transmits the data and sender user identification information of the data are not stored in correspondence to each other.

A data transmission server for transmitting data received from a client to a destination, the data transmission server, comprising:

• first memory means for storing client identification information and user identification information uniquely determined by authentication ID and password authenticated by Post Office Protocol (POP), the client identification information and the user identification information being stored in correspondence to each other;
• first determining means for determining whether the client identification information of the client which transmits the data and sender user identification information are stored in said first memory means in correspondence to each other;
• and
• controlling means for controlling not to transmit the data received from said client to the destination when the first determining means determines that the client identification information of the client which transmits the data and the sender user identification information of the data are not stored in said first memory means in correspondence to each other.