| 摘要 |
<p>A message transmission server, which transmits text messages, comprises a message receiving unit which receives a text message from a sending terminal, a number comparing unit which compares a sending number with a callback number included in the received text message, a number determining unit which determines whether the callback number is a valid number if the sending number is different from the callback number as a result of the comparison, and a blocking unit which blocks transmission of the text message if the callback number is not the valid number as a result of the determination.</p> |
